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chemistry of household mgredients / Simon Quellen Field. - 1st ed. p.cm. Includes index.

ANTIFREEZE

in Your

TOOTHPASTE

The Chemistry of

Household Ingredients

SIMON O!dELLEN FIELD

Library of Congress Cataloging-in-Publication Data

Field, Simon (Simon Quellen)

Why there's antifreeze in your toothpaste: the

chemistry of household mgredients / Simon Quellen Field. - 1st ed. p.cm. Includes index.

ISBN-13: 978-1-55652-697-8

ISBN-10: 1-55652-697-0

I. Chemicals.

Chemical elements.

Organic

compounds.

Inorganic compounds.

I. Title. QD47l.F5652007 540-dc22 2007025849

Cover photo: Mark Harwood/Stone Images

Cover and interior design: Scott Rattray

Structural illustratIOns: Michael Rattray

All rights reserved

First editIOn

Published by Chicago Review Press, Incorporated

814 North Franklin Street

Chicago, illinoIs 60610

ISBN-13: 978-1-55652-697-8

ISBN-IO: 1-55652-697-0

Printed in the UnIted States of America

543 2

Introduction

Xl

How to Read Structural Formulas

:xv

Preservatives

Ultraviolet Light Absorbers

Benzophenone

Para-amino Benzoic Acid (PABA)

Focus: Sunscreen

Zinc Oxide

Titanium Dioxide

Color Stabilizers

Sulfur Dioxide

Sodium Bisulfite

Antioxidants

Tocopherols (Vitamin E)

Ascorbic Acid (Vitamin C)

Erythorbic Acid

Butylated Hydroxyanisole (BHA)

Butylated Hydroxytoluene (BHT)

Honey

Sodium Citrate

Lecithin

Propyl Gallate

Antimicrobials

Sodium Benzoate

Benzoic Acid

Potassium Sorbate

Sorbic Acid

Natamycin

Triclosan

Triclocarban

Hexachlorophene

Acetic Acid (Vinegar)

Sodium Chloride (Salt)

Focus: Table Salt

Sugars

Focus: Sweeteners

Calcium Propionate

Sodium Propionate

Imidazolidinyl Urea

Methyl Paraben

Isothiazolinone

Methylisothiazolinone

Methylchloroisothiazolinone

Lactic Acid

Sodium Nitrite

Sodium Nitrate

DMDM Hydantoin

Glycols

42 2-bromo-2-nitropropane-l,3-diol 43

Buffers

Sodium Citrate

Aminomethyl Propanol (AMP)

Tetrasodium Pyrophosphate

Phosphoric Acid

Chelating or Sequestering Agents

(Water Softeners) 49

Ethylene Diamine Tetra Acetic Acid (EDTA)

Diethylene Triamine Pentaacetic Acid

Phosphoric Acid

Sodium Citrate

Tetrasodium Pyrophosphate

Tetrasodium Etidronate

Sodium Carbonate

Alcohols and Phenols

Ethanol

Stearyl Alcohol

Cetyl Alcohol

Glycerin

Menthol

Waxes

Esters

Flavorings

Acids

Acetic Acid (Vinegar)

Citric Acid

Lactic Acid

Stearic Acid

Phosphoric Acid

Fumaric Acid

Tartaric Acid

Esters

Methyl Vanillin

Ethyl Vanillin

Denatonium Benzoate

Other Flavorings

Vanilla

Monosodium Glutamate (MSG)

Sweeteners

Sucrose

Invert Sugar

Fructose

High-Fructose Corn Syrup

Neotame

Acesulfame Potassium

Aspartame

Sucralose

Focus: Soft Drinks

Saccharin

Lactose

Poorly Absorbed Carbohydrates and Sugar Alcohols

Sorbitol

Mannitol

Xylitol

MaItitol

Hydrogenated Starch Hydrosylate (HSH)

Salt Substitutes

Potassium Chloride

Fats

Tristearin (Saturated Fats)

Focus: Fats

Trilinolein (Polyunsaturated Fats)

Trilinolenin (Omega-3 Fats)

Fat Substitutes

Olestra

Salatrim

Guar Gum

Focus: Ice Cream

Locust Bean Gum

Xanthan Gum

Colors

Annatto

Beta-carotene

Carmine

III

Focus: Food, Drug, and Cosmetic Colors

Saffron

Turmeric

Titanium Dioxide

Allura Red

Indigo

Caseinates

Ferrous Gluconate

Moisture Controllers

Glycerin

Sorbitol

Sodium PCA

Mannitol

Propylene Glycol

Butylene Glycol

Panthenol

Emulsifiers

Lecithin

Phosphoric Acid

Sorbitan Monostearate

Polysorbate 80

Glycerol Monostearate (Mono- and Diglycerides)

Tetrasodium Pyrophosphate

Focus: Whipped Cream

Stabilizers and Thickeners

Corn Syrup

Sodium Caseinate

Calcium Caseinate

Polyethylene Glycol (PEG)

Polypropylene Glycol (PPG)

Lecithin

Methylcellulose

Sodium Carboxymethylcellulose

Xylenesulfonates

Agar

Gelatin

Pectin

Alginates

Starch and Modified Starch

Carrageenan

Guar Gum

Locust Bean Gum

Brominated Vegetable Oil

Gum Arabic

Xanthan Gum

Dough Conditioners and Whipping Agents

Sodium Stearoyl Lactylate

Calcium Stearoyl Lactylate

Sodium Stearoyl Fumarate

Focus: Bread

Potassium Bromate

Carrageenan

Tetrasodium Pyrophosphate

Fumaric Acid

Stimulants

Caffeine

Theobromine

Ephedrine

Medicines

Benzoyl Peroxide

Focus: Acne Medicines

Salicylic Acid

Sulfur

Resorcinol

Hydrogen Peroxide

Sodium Bicarbonate

Hydroquinone

Antibiotics

Triclosan

Triclocarban

Hexachlorophene

Pain Relievers

Potassium Nitrate

Benzocaine

Tramadol

Acetylsalicylic Acid (Aspirin)

Acetaminophen

Ibuprofen

Naproxen

AIIantoin

Menthol

Methyl Salicylate, Ethyl Salicylate, Glycol Salicylate

Camphor

Methyl Nicotinate and Benzyl Nicotinate

Capsaicin

Bleaching Agents

Sodium Hypochlorite

Focus: Bleach

Calcium Hypochlorite

Hydrogen Peroxide

Benzoyl Peroxide

Borax

Sodium Perborate

Sodium Carbonate Peroxide

Sodium Dichloroisocyanurate

Hydroquinone

Surfactants

Ammonium Lauryl Sulfate

Focus: Shampoo

Sodium Lauryl Sarcosinate

Lauryl Glucoside

Cocamidopropyl Betaine

Sodium Stearate

Focus:Soap

Sodium Dodecylbenzenesulfonate

Sodium Isethionate

Focus: Detergents

Xylenesulfonates

Foam Stabilizers

Cocamide MEA, Cocamide DEA, Cocamide TEA

Tetrasodium Pyrophosphate

Conditioners

Cetyl Alcohol

Cetrimonium Chloride

Silicones

Panthenol

Propellants

Nitrous Oxide

Isobutane

Dimethyl Ether

Polymers and Glues

Vinyl Acetate

Focus: Hairspray

Vinyl Alcohol

Methacrylate

Silicones

Abrasives and Dental Additives

Hydrated Silica

Focus: Toothpaste

Stannous Fluoride

Sodium Fluoride

Sodium Monofluorophosphate

Index

Introduction

This book started in my shower.

The label on my shampoo bottle listed many compounds, and,

due to my interest in chemistry, most of them were familiar or had

obvious functions. However, one compound stood out as puzzling

sodium chloride. Why was there salt in my shampoo? Since I wasn't likely to be eating it, I doubted it was for seasoning, despite the strawberry aroma of the liquid. It could have been used as a preservative, but the remaining ingredients were more likely to kill microbes than salt was. Once dry and dressed, I was still curious, so I wrote a letter to the manufacturer asking why there was salt in my shampoo. I received a surprisingly enlightening response from the company. Someone there had actually discussed the issue with a chemist and sent back to me an answer that made sense.

The ingredients in the shampoo come from many different man-

ufacturers, in many different places around the world. From day to day, a particular batch of shampoo may differ significantly from the previous day's batch in the amount of moisture brought in with those ingredients. Salt has the effect of thickening the mixture, and is added to each batch in the amount needed to raise the viscosity to a speci- fied level. Consequently, the customer gets a product that pours the same way each time. This consistency is important to the customer, because a watery product can cause suspicions about value or about possible tampering. xi

xii

Introduction

I have told this story many times when teaching chemistry to popular audiences. There are thousands of chemical compounds in the ingredients lists of products we use every day. If you're compari- son shopping, knowing what each compound is doing in the product has obvious benefits. However, it also provides a sneaky way of teach- ing simple chemistry to people who had no idea they would find it so interesting and who see chemistry simply as the domain of nerds with masking tape on their eyeglasses.

Sprinkled throughout this book are sidebars focusing on foods

and consumer products that use interesting ingredients; the sidebars explain just what those ingredients are doing in those particular products.

The bulk of the book is a more in-depth discussion of each com- pound, usually accompanied by a structural formula, a picture of the chemical that allows it to be compared to others.

It is in these sections that you will occasionally find clearly marked "Chemistry Lessons." If I have done my job properly, these will be interesting, and they'll relate to the compound that caught your interest in the first place.

This book can act as a reference.

You can use the index to look up an ingredient you find on a label and find out more about it.

It may point you to other pages or other compounds; you may enjoy read- ing the book in this random fashion, rather than from front to back.

Feel free to do so.

Feel free to skip over sections that don't relate to what you are trying to find out.

The book will still be there later when you have another question.

This book is not about scaring people.

So much of the informa- tion out there about additives or chemicals in common products is written to alarm people into changing their behavior in ways that potentially enrich the writer.

They point to the MSDS for a com- pound-the Material Safety Data Sheets-that list all the dire conse- quences and safety precautions associated with a compound.

An MSDS can be quite frightening.

Here is an excerpt from a typ-

ical MSDS

Introduction

XIII

Hazards Identification

WARNING! CAUSES EYE IRRITATION.

Lab Protective Equip: GOGGLES; LAB COAT

May cause mild irritation to the respiratory tract. Very large doses can cause vomiting, diarrhea, and prostration. Dehydration and congestion occur in most internal organs. Hypertonic solutions can produce vio- lent inflammatory reactions in the gastrointestinal tract. May irritate damaged skin; absorption can occur with effects similar to those via ingestion. Causes irritation, redness, and pain.

First Aid Measures

Remove to fresh air Get medical attention for any breathing difficulty.

If large amounts were swallowed, give water to drink and get medical advice.

Wash exposed area with soap and water.

Get medical advice if irritation develops.

Immediately flush eyes with plenty of water for at least 15 minutes, lifting upper and lower eyelids occasionally.

Get medical attention if irritation persists.

In the event of a fire, wear full protective clothing and NIOSH-approved self-con- tained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode Ventilate area of leak or spill.

Wear appropriate personal protective equipment.

Keep in a tightly closed container, stored in a cool, dry, ventilated area Protect against physical damage.

Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

Wear protective gloves and clean body-covering clothing.

Use chemical safety goggles.

Maintain eye wash fountain and quick-drench facili- ties in work area When heated to above 801°C (1474OF) it emits toxic fumes of chloride and sodium oxide.

Oral rat LD50: 3000 mg/kg.

Inhalation rat LD50: > 42 gm/m 3 /1 H

Skin rabbit LD50' > 10 gm/kg. Investigated as a mutagen, reproductive effector.

Label Hazard Warning

WARNINGI CAUSES EYE IRRITATION

Label Precautions

Avoid contact with eyes. Wash thoroughly after handling.

Label First Aid'

In case of eye contact, immediately flush eyes with plenty of water for at least 15 minutes Get medical attention if irritation develops or persists.

Product Use

Laboratory Reagent.

xiv

Introduction

After reading that, you might expect that such a dangerous chem- ical had no business being around people, especially children.

Yet in actuality, it's a chemical we can't live without: salt.

And it's safe enough to put in shampoo.

What this illustrates is that an MSDS describes the dangers of large industrial quantities of a substance, not the tiny amounts usu- ally found in consumer products.

Nonetheless, once you are experi- enced at reading an MSDS, it is a good place to get information on the safety of a chemical compound.

In this book I cover safety issues only occasionally-and briefly.

To do a more thorough job of that would require a much larger book, and there is already a wealth of information available.

One should be wary, however, of authors who advise against a brand of toothpaste because "it has antifreeze in it!" Just before the publication of this book, a media frenzy arose over the discovery that a Chinese-made toothpaste contained the toxic additive diethylene glycol, which the Food and Drug Administration had warned had a "low but meaningful risk of toxicity and injury" to people with liver disease, people with kidney disease, and children.

It was a poisoning incident involving diethylene glycol in 1937 that gave new regulatory powers to the FDA.

And diethylene glycol makes a pretty good antifreeze.

But diethylene glycol is not glycerin or propylene glycol, both of which are nontoxic toothpaste ingredients that also have antifreeze properties, in addition to the emulsifying and moisturizing proper- ties that are useful in toothpastes, cosmetics, baby wipes, bubble baths, medicines, flavorings, and shampoos.

So when someone warns that there is antifreeze in your tooth- paste, ask which antifreeze.

Some are illegal adulterants added by criminal cost-cutters, and their products are quickly recalled.

Others (like glycerin, propylene glycol, or salt) are "generally recognized as safe" and are reasonable household ingredients.

Fear may help other folks to sell books or newspapers or organic toothpaste.

But I hope curiosity is the reason you are reading my book.

How to Read Structural Formulas

Throughout this book, the description of each ingredient will include its chemical formula. This is often quite useful in comparing the ingredient to others, understanding how it performs its function, and evaluating how it interacts with other compounds. Some of the formulas might look intimidating at first, but you can actually learn to read them in a few minutes, as the following text will show.

Simple Formulas

Some formulas, such as the formula for table salt, are very simple. You don't need a picture, just a description of the two elements that make

it up: sodium and chlorine. The formula is

NaCI

Other compounds are also fairly simple, although they may con- tain more elements. For example, phosphoric acid, a common ingre-

dient used to provide tartness in soft drinks, is

xvi

How to Read Structural Formulas

This formula says it is made up of three hydrogen atoms, one atom of phosphorus, and four atoms of oxygen.

A molecule you probably already know is water

Full Structural Formulas

For some compounds, it is especially useful to know the shape of the molecule. While this is critically important in large molecules made with a backbone of carbon, called organic molecules, it is often inter- esting in simpler molecules as well. The formula for water might cause you to think that a hydrogen atom was attached to another hydrogen

atom, and then an oxygen atom was attached to them

H-H-O

That would be wrong, however, since a hydrogen atom can only form a bond with one other atom. Moreover, oxygen can bond with

two other atoms, so a better picture would look like this

H-O-H

As it turns out, however, the angle between the bonds is not 180 degrees, as that picture would make it seem, but 105 degrees. This fact

is important in understanding some curious facts about water

" / o The electrons that the hydrogen atoms share with the oxygen are located between the hydrogen atoms and the oxygen atom. This leaves the hydrogen atoms with a little bit of a positive charge, and the oxy- gen atom with a little bit of a negative charge. This polar arrangement means that the molecules prefer to align in certain ways, because the positive sides attract the negative sides. This gives water its surface

How to Read Structural Formulas

xvii tension. It explains why ice crystals arrange in hexagons and take up more space than liquid water, making ice less dense than water, so it floats. It also explains how water molecules can dissolve other polar molecules, such as table salt. The water molecules surround the pos- itive sodium ions and the negative chlorine ions, and prevent them from getting back together.

Simplified Structural Formulas

I have already said that a hydrogen atom can only bond with one other atom. This is because it only has one electron to share. The element carbon has four electrons it can share easily, and so it can bond to four different atoms at a time. Because carbon is so versatile, it can form very complex molecules. These complex molecules are what led to life on this planet; living things are primarily made of large molecules with a backbone of carbon.

Simple carbon compounds such as methane are often written

using nonstructural formulas, such as

or the structural formulas just discussed

H-C-H

But when the molecules start getting larger, all those letters for carbon and hydrogen start to clutter up the page, making it hard to see detail. Since carbon has four bonds to fill, and because hydrogen is the most likely atom to be attached to carbon in an organic molecule, chemists invented a shorthand notation that is easier to read and draw.

xviii

How to Read Structural Formulas

In this shorthand, they assume that any vertex between two lines contains a carbon atom unless specified otherwise. If there are several carbons in a row, they will make the lines join at angles, so that they can count the carbons if need be. Chemists also say that any carbon that has fewer than four lines from it is assumed to have a hydrogen atom filling all the remaining bonds. Thus the molecule propane (C3Hs), which has three carbons

in a row, has all of the remaining bonds filled with hydrogen

H-C-C-C-H

and becomes the much simpler looking picture

There is a carbon at each end and one in the middle. The carbon atoms at each end have three remaining bonds, which are filled with three hydrogen atoms. The carbon in the middle has only two bonds left, so there are two hydrogen atoms there. Now, for simple molecules like propane, this is not much of an improvement. It is easier to draw, but the reader has to do some think- ing to figure out what the molecule is. However, with larger molecules, the simplification really helps to keep the picture uncluttered. Con-

sider the molecule for aspartame, which would look like this

How to Read Structural Formulas

xix

It simplifies to this

II

How to Read Structural Formulas

Three-Dimensional Structural Formulas

Sometimes it is important to know the three-dimensional structure of a molecule. In glucose, for example,

OH

it is important to know which side of the molecule the various hydroxyl groups (the OH subunits) are on. Flipping one of them from

the bottom to the top changes the sugar from glucose to galactose

OH

which is much less sweet than glucose. The formula shown uses darker lines to indicate that some parts of the molecule are closer to the reader.

Preservatives

1 Preservatives have become the favorite target of people who want you to fear your food.

Most preservatives are things you would not want to eat.

Most preservatives taste bad and are toxic in large quantities, so it is not surprising that they have a bad reputation.

Preservatives generally fall into four categories.

There are ultravi- olet/UV light absorbers (to prevent light from creating harmful and bad-tasting toxins), color stabilizers, antioxidants, and antimicrobials.

One excellent UV protector for foods is PABA, a B vitamin.

Like- wise, many of the same antioxidants we ingest as health supple- ments-such as vitamin C and a similar chemical, erythorbic acid; vitamin E; and lecithin, a source of the important nutrients choline and inositol-occur naturally in food.

Some simple foods can be preservatives in their own right.

Honey, salt, sugar, lactic acid, and vinegar are all examples of foods that inhibit microbial action.

Some health professionals recommend con- suming phytoestrogens from foods such as soybeans to achieve vari- ous health benefits.

The phytoestrogens in the paraben family, found in blueberries, kill molds and fungi and are often added to food as preservatives.

But you don't have to choose between having sodium benzoate

or E. coli bacteria in your soda. Bacteria can be controlled through pasteurization, a process that is used for milk but for some reason not for soft drinks.

Why There's Antifreeze in Your Toothpaste

Ultraviolet LightAbsorbers

Benzophenone

Chemical Formula

C6Hs-C(O)-C6Hs

IIo

Synonyms

Diphenyl ketone • benzoyl benzene • phenyl ketone • diphenyl-

methanone· alpha-oxodiphenylmethane • alpha-oxoditane

Description

White crystals with a rose- or geranium-like odor.

Uses

Benzophenone is used to prevent ultraviolet light from damaging scents and colors in products such as perfumes and soaps. It allows the manufacturer to package the product in clear glass or plastic. Without it, opaque or dark packaging would be necessary. It can also be added to the plastic packaging itself as a UV blocker. Benzophenone is also sometimes used as a flavoring agent. Ultraviolet light is often divided into two types, UV-A, which has a longer wavelength (320-360 nm) and UV-B, which has a shorter wavelength (280-320 nm). Shorter wavelengths are higher energy wavelengths. UV-B is more damaging than UV-A. Some UV blockers are optimized to block the shorter wavelengths while letting the longer wavelengths get through.

Preservatives

Variants

There are many variants of benzophenone. They often have numbers after the name, a type of shorthand to indicate which variant is in use. The variations change features, such as solubility or the ease and func- tionality of bonding with plastics used in packaging. For example, ben- zophenone-2 is used in alcohol-based products, while benzophenone-5 is used in water-based products. Benzophenone-6 is used in nail pol- ish, and benzophenone-9 is used in bath and skin-care products. Some examples are shown below.

Benzophenone-3 (2-hydroxy-4-methoxybenzophenone)

Chemical Formula

HOCsH3(OCH3)COCsHs

Benzophenone-3 can be added to plastic packaging as a UV

blocker.

Benzophenone-4 (2-benzoyl-5-methoxy-1-phenol-4-sulfonic acid)

Chemical Formula

C14H120SS

Why There's Antifreeze in Your Toothpaste

II

\o 0=8=0

OH

Benzophenone-4 is a water-soluble form used in cosmetics, hair- sprays, and hair dyes.

Benzophenone-bx-ahbp (4-allyloxy-2-hydroxy benzophenone)

H2C

II

OH

0 This form of benzophenone is also added to plastic packaging as a UV blocker. It bonds with the plastic and will not migrate out.

Other Examples

Benzophenone-1 (2,4-dihydroxy benzophenone)

Benzophenone-2 (2,2' ,4,4'-tetrahydroxy benzophenone)

Benzophenone-5 (2-hydroxy-4-methoxy-5-sulfonyl benzophenone

sodium salt)

Preservatives

Benzophenone-6 (2,2'-dihydroxy-4,4'-dimethoxy benzophenone)

Benzophenone-9 (2,2'-dihydroxy-4,4'-dimethoxy benzophenone-

5,5'-disulfonate sodium)

Benzophenone-12 (2-hydroxy-4-N-oetoxy benzophenone)

Other UV Blockers

Amyl p-methoxy einnamate

Oetyl p-methoxy einnamate

Para-amino Benzoic Acid

Chemical Formula

O~

OH

Synonyms

PABA· 4-aminobenzoic acid· p-aminobenzoic acid· ethoxylated

ethyl 4-aminobenzoic acid (PEG-25 PABA)

Description

White powder. Para-amino benzoic acid (PABA) is considered to be in the B- complex vitamin family. The human body can make it from folic acid,

since PABA forms the middle part of that vitamin

Why There's Antifreeze in Your Toothpaste

H"

II

"N~~

II ~

H-N

Folic acid, showing PABA inside

; ~ : H a

II

I~~

:~i N /I a

OH

This means that in the strictest sense, PABA is not a vitamin, because the body can manufacture it. But in this sense, too, vitamin A is not technically a vitamin, as the body makes that from beta-carotene. Bacteria in the intestines produce folic acid if there is PABA pres- ent. Microbes need PABA, but it is not strictly necessary for humans. A class of drugs that simulate PABA, sulfa drugs, can fool the microbes into trying to use them instead of PABA, which causes them to die. This is why people taking sulfa drugs are advised not to take PABA at the same time.

Uses

PABA is taken orally in vitamin supplements. However, its widest use is as a sunscreen. Taking it orally will not protect a person from the sun; as a sunscreen PABA acts as a topical dye that absorbs ultravio- let light. To block UV rays from the sun, a person needs to paint it directly onto the skin. PABA is acidic, which means it can sting if it gets in the eyes. Some people are sensitive to PABA when it is applied to their skin. PABA also darkens and can stain clothing. For these reasons, modified forms of PABA have become popular as sunscreens. PABA can be reacted with long-chain alcohols to form PABA esters, such as polyethylene

glycol 25 PABA

Preservatives

7 0, /'-. /'-. ,0 0

-D--- H/

'V' '0'

'V' ~O~ ~O~N

f ,

II

H ........ ~O~ ~O~

~O"-./"

0 0 0 -- 0

/,,~O~~O~~

0 0 0

PEG-25 PABA ester

This PABA molecule eliminates the irritation and staining problems.

Other PABA esters are glycerol PABA, padimate A, and padimate O. ~ Chemistry Lesson Molecules absorb light when the light's wavelength is just the right length to cause electrons in the molecule to vibrate in time with the light.

The electrons resonate in the molecule.

In some molecules, the electrons are not bound to a single atomic nucleus but instead roam free across several nuclei in what are called resonance bonds.

You may notice that sometimes a six-sided ring is shown with alternating double and single bonds, while at other times it is shown with a circle inside.

Both forms are showing the same thing.

The circle just draws attention to the fact that the bonds don't really alternate between double and single-they are more like one and a half bonds.

On average, the electron spends half of the time in one place, and half in the other.

In para-amino benzoic acid, there is another resonance structure right next to the six-sided ring.

It is a carboxyl group, shown with a single bond between carbons, and a double bond between the carbon and the oxygen.

This is also a place where the electron can bounce around between the three nuclei.

It is even possible for an electron to move back and forth across all of the resonance bonds-from one end of the molecule to another.

This lets the electron slosh back and forth like water in a bathtub.

Why There's Antifreeze in Your Toothpaste

the case of para-amino benzoic acid, the rhythm of the sloshing matches the frequency of UV-B light. The electron can move in time with the light wave and absorb its energy. The energy is later released as photons of longer wavelength light such as heat. Knowing this, chemists can design other molecules that have resonance structures that will catch UV-B rays. One such molecule is benzophenone, and a derivative called benzophenone-3, also known as oxybenzone.

Benzophenone

OH

Benzophenone-3 (oxybenzone)

Notice that both molecules have the six-sided ring, called a ben- zine ring, and a carboxyl group (the carbon-oxygen double bond). These molecules also protect against UV-A. You can see that they have longer chains of resonance bonds, which means that they will resonate at longer wavelengths. Getting more creative with the chemistry, a chemist can add other desirable features to these molecules. Adding long chains of hydro- carbons can help it mix better with suntan oils to spread more easily on the skin. The resonance bonds can be modified a little bit to get a broader absorption range, expanding into the longer wave UV-A region.

Preservatives

9 Such a designer molecule is octocrylene and a similar one known as avobenzone. o

II

==00 eN

Octocrylene

Other molecules with the benzine ring and carboxyl group also

have side chains added to make them better sunscreens. Two popular

ones are 2-ethylhexyl salicylate

II

CC

o~ ~

OH

2-ethylhexyl salicylate

and homomethyl salicylate, also known as homosalate

o"A rro~ ~

OH

Homomethyl salicylate

Why There's Antifreeze in Your Toothpaste

Other salicylates used as sunscreens are 4-isopropylbenzyl salicy- late, and triethanolamine salicylate, which goes by the trade name Tro- lamine Salicylate. Another class of UV-B absorbers is the cinnamates. /"v0

II

° ° ""

Octyl methoxycinnamate

These molecules are not water soluble, are able to stick to the skin well, and are highly effective in water-resistant sunscreens. Others in this family are isopentenyl-4-methoxycinnamate, also known as isoamyl 4-methoxycinnamate, and cinoxate. As you can see, there are many molecules that will absorb ultra- violet light. There are many more in use than I have described here. But they all have resonance bonds in common.

Focus: Sunscreen

We love the sun. We complain about rainy days, and we look forward to summers at the beach. But we hate sun- burns, wrinkled skin, and melanomas. All of those nasty things are the result of the ultraviolet rays that come with the warmth and light of sunshine.

Preservatives

11 There are a large number of chemicals used to block ultravio- let light, either to protect the user's skin or to protect a product from being damaged (colors fading, scents decomposing, etc.) Some are vitamins, such as PABA.

Some are opaque powders used in creams, such as zinc oxide and titanium dioxide.

Others, such as benzophenone, are designed to be invisible (they don't block visible light).

There are two ways in which chemicals can protect the skin from ultraviolet light: they can either absorb the light or reflect the light.

Zinc oxide and titanium dioxide reflect or scatter light of many frequencies, from infrared through ultraviolet.

That is why these chemicals appear opaque white.

If you don't want to paint yourself white, you can paint your- self with a color that absorbs ultraviolet light but is transparent to visible light.

Ultraviolet light is often divided into two types: UV-A, which has a longer wavelength (320-360 nm), and UV-B, which has a shorter wavelength (280-320 nm).

Shorter wavelengths mean higher energies.

UV-B is more damaging than UV-A.

Some UV blockers are optimized to block the shorter wavelengths while letting the longer wavelengths get through.

SPF (sun protection factor) numbers only describe UV-B protection.

A high SPF can still let UV-A through.

UV-C is the shortest wavelength of ultravi- olet light, but it is effectively screened out by the ozone layer of the atmosphere.

Because governments only allow certain per- centages of each UV-absorbing compound, the higher SPF for- mulations generally have several UV absorbers in them.

UV-B causes sunburn, but UV-A damages collagen (connec-

tive tissue) and blood vessels, causing aging effects such as wrinkled skin. Finally, sunscreens block the body's ability to make vitamin 0 from sunlight. If you are using sunscreen a lot, or if you do not get much sun, a doctor may advise you to add supplemental vita- min 0 to your diet.

Why There's Antifreeze in Your Toothpaste

Zinc Oxide

Chemical Formula

ZnO

Description

White powder.

Uses

Zinc oxide is a white powder that makes a very opaque paste when mixed with water or oils. It is used as a sunblock and as a colorant in toothpastes and cosmetics. Zinc oxide is used in many of the same products as titanium dioxide.

Titanium Dioxide

Chemical Formula

Ti02

Description

White powder.

Uses

Titanium dioxide makes a very opaque paste when mixed with water or oils. It is used as a sunblock and as a colorant in toothpastes and cosmetics. Titanium dioxide is used in many of the same products as zinc oxide.

Color Stabilizers

Sulfur Dioxide

Chemical Formula

Preservatives

Description

Acrid gas produced when sulfur is burned in air.

Uses

Sulfur dioxide is a reducing bleach and can counter the effects of oxi- dizing bleaches, thus preserving color in fruits dried in the sun. The combination of fruit acids and ultraviolet light would otherwise react with the colorful compounds, making the fruit pale. Sulfur dioxide is produced by burning sulfur in air for preserving fruit, or by reacting sodium bisulfite in water as part of the process to make products such as wine. Sulfur dioxide also kills yeasts, molds, and bacteria.

Sodium Bisulfite

Chemical Formula

NaHS03

Synonyms

Monosodium sulfite· sodium hydrogen sulfite· sodium sulhydrate • sulfurous acid· sodium salt

Description

Clear or milky white liquid with a sulfurous odor.

Uses

Sodium bisulfite is used in almost all commercial wines to prevent oxidation and preserve flavor. It releases sulfur dioxide gas when added to water or products containing water. The sulfur dioxide kills yeasts, fungi, and bacteria in grape juice before fermentation. When the sulfur dioxide levels have subsided, after about twenty-four hours, fresh yeast is added for fermentation. Sodium bisulfite is often combined with an acid such as citric acid to make it produce gas faster. It is also used to sterilize winemaking

Why There's Antifreeze in Your Toothpaste

equipment. It is later added to bottled wine to prevent oxidation, which would change the wine to vinegar and cause it to turn brown. The sulfur dioxide displaces oxygen in the bottle and dissolves in the wine. Without it oxidized wine can turn orange or brown and taste like raisins or cough syrup. In fruit canning, sodium bisulfite is used to kill microbes and to prevent the browning caused by oxidation.

Antioxidants

Tocopherols

Chemical Formula

HO

o a -tocopherol

Synonyms

Vitamin E

Description

Light yellow liquid.

Uses

Vitamin E is added to some food products as a nutrient, but it is bet- ter known for its antioxidant properties, which protect oils and fats from oxidation. Tocopherols come in various forms only slightly different from the a-tocopherol shown in the structural formula above. Its 13 and'Y forms differ in where the methyl groups are attached to the ring struc- ture. An ingredients list may single out the a form, or may just list "mixed tocopherols."

Preservatives

Ascorbic Acid

Chemical Formula

HO

Synonyms

Vitamin C

HO

OH

Description

Sour-tasting white powder.

Ascorbic acid-vitamin C-is an essential nutrient that the

human body cannot manufacture from other compounds. It is needed for the formation of collagen, the protein that makes up con- nective tissue, and is essential to muscles, bones, cartilage, and blood vessels. It is a strong antioxidant, preventing damage from oxygen free radicals.

Uses

Ascorbic acid is added to many foods for its nutritive value. It is used extensively as an antioxidant to prevent flavors and colors from being damaged by oxidation. It is often used in canned or frozen fruits to prevent the browning that accompanies oxidation. While not as pow- erful an antioxidant as sodium bisulfite, it has a better nutritional reputation. An isomer (molecule with the same number and type ofatoms but in a different formation) of ascorbic acid called erythorbic acid is often used as a less expensive antioxidant than ascorbic acid. It has little or no effect as a vitamin, but it has the same antioxidant properties. To make ascorbic acid soluble in fats, it is reacted with fatty acids, such as palmitic acid, to form ascorbyl palmitate. This is used to pre- vent oxidation in fats and oils.

Why There's Antifreeze in Your Toothpaste

Erythorbic Acid

See Ascorbic Acid entry, page 15.

Butylated Hydroxyanisole

Chemical Formula

CHPCeH3(OH)C(CH3b

Io

OH

Synonyms

BHA· 2-tert-butyl-4-hydroxyanisole • 3-tert-butyl-4-hydroxyanisole

Description

White or slightly yellow waxy solid.

Uses

BHA is an antioxidant. It reacts with oxygen free radicals. It can thus slow down the rate at which ingredients in a product oxidize in direct contact with air, a process that can cause changes in the taste or color. BHA can be added to the food itself, or to the packaging material, and it is used primarily to prevent fats from becoming rancid.

Preservatives

Butylated Hydroxytoluene

Chemical Formula

C6H2(OH)(CH3)[C(CH3)3h

OH

Synonyms

BHT· 2,6-di-tert-butyl-4-methylphenol • dibutylated hydroxytoluene

Description

White crystals or crystalline powder.

Uses

BHT is an antioxidant. It reacts with oxygen free radicals. It can thus slow down the rate at which ingredients in a product oxidize in direct contact with air, a process that can cause changes in the taste or color. BHT can be added to the food itself, or to the packaging material, and it is used primarily to prevent fats from becoming rancid.

Honey

Chemical Formula

OH

Glucose

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OH

Fructose

Description

Viscous yellow liquid.

Uses

Honey is primarily fructose and glucose (in that order), with a little sucrose (about 1 percent), less than 10 percent other sugars, and about 17 percent water. Honey's water content is high enough that it remains liquid, but low enough to make it thick and prevent spoilage. Because it contains relatively little water, microorganisms that encounter it die as the water in them is extracted by osmosis. In addition, as honey is diluted with water, a chemical reaction between glucose, water, and oxygen produces small amounts of hydrogen peroxide and gluconic acid. The slow release of hydrogen peroxide makes honey a mild antiseptic. The acidity of honey also reduces the number of organisms that can live in it. Honey is mostly used as a sweetener, but it can also function as an antiseptic for wounds and as a preservative.

Preservatives

Sodium Citrate

Chemical Formula

O~

ONa

NaO

Synonyms

Trisodium citrate

Description

White odorless crystals. =0

ONa

Uses

Sodium citrate is used in ice cream to keep the fat globules from stick- ing together. Citrates and phosphates both have this property. It is also an anticoagulant. As a buffering agent, sodium citrate helps maintain pH levels in soft drinks. As a sequestering agent, it attaches to calcium ions in water, which keeps them from interfering with detergents and soaps.

Compounds with similar functions are sodium carbonate,

sodium EDTA, phosphoric acid, pentasodium pentetate, tetrasodium etidronate, and tetrasodium pyrophosphate.

Why There's Antifreeze in Your Toothpaste

Lecithin

Chemical Formula

II

0- (a0 II -N'

I)

I ~O-P-O

IIo

Synonyms

Phosphatidylcholine

Description

Light brown or yellow solid. Lecithin is a phospholipid, a class of compounds that make up cell membranes throughout the body. It is produced in the liver if the diet contains enough of the raw ingredients.

Uses

Lecithin is widely used as an emulsifying agent, allowing oil and water to mix. It is used in ice creams, salad dressings, and cosmetics, and it is the main ingredient in nonstick cooking sprays. Lecithin is the emulsifier in egg yolks that allows the oil and water to mix to make mayonnaise. Lecithin is also an antioxidant, helping to keep fats from going rancid (but in the process, going rancid itself). Lecithin is often taken as a dietary supplement, since it contains the B vitamin choline.

Propyl Gallate

Chemical Formula

HO

OH

II O~

Preservatives

Synonyms

Gallic acid· propyl ester· N-propyl gallate· propyI3,4,S-trihydroxy- benzoate

Description

Beige powder. Propyl gallate is an antioxidant. It protects against oxidation by hydrogen peroxide and oxygen free radicals in a catalytic manner sim- ilar to superoxide dismutase.

Uses

Propyl gallate is used to protect oils and fats in products from oxi- dation. It is used in foods, cosmetics, hair products, adhesives, and lubricants. It is synergistic with ascorbyl palmitate.

Antimicrobials

Sodium Benzoate

Chemical Formula

O~

ONa

Synonyms

Benzoate of soda

Description

White powder or crystals. Sodium benzoate converts to benzoic acid in acidic mixtures. Benzoic acid has good antimicrobial features but does not dissolve well in water, whereas sodium benzoate dissolves very well in water.

Why There's Antifreeze in Your Toothpaste

Uses

Sodium benzoate is used in acidic foods and products to control bac- teria, mold, yeasts, and other microbes. It interferes with their ability to make energy. Because it only converts to benzoic acid in acidic environments, it is not used for its antimicrobial action unless the pH is 3.6 or below. In the food industry, it is used in items such as jams, salad dressing, juices, pickles, and carbonated drinks. It is also used as a corrosion inhibitor in automotive antifreeze products.

Benzoic Acid

Chemical Formula

O~

OH

Synonyms

Benzenecarboxylic acid· carboxybenzene • phenyl carboxylic acid· phenylformic acid

Description

White powder or crystals with a strong odor.

Uses

Benzoic acid has good antimicrobial features, but because it does not dissolve well in water, sodium benzoate is often used. Sodium ben- zoate converts to benzoic acid in acidic solutions, and dissolves very well in water.

Benzoic acid is an ingredient in toothpastes and mouthwashes,

cosmetics, and deodorants.

Preservatives

Potassium Sorbate

Chemical Formula

o ~

OK

Description

White crystals.

Uses

Potassium sorbate is a polyunsaturated fatty acid salt. It is used to inhibit molds, yeasts, and fungi in many foods, including cheese, wine, and baked goods. It is the potassium salt of sorbic acid.

Sorbic Acid

Chemical Formula

o ~

OH

Description

White crystalline powder. Sorbic acid is a polyunsaturated fat.

Uses

Sorbic acid is used to inhibit molds, yeasts, and fungi in foods such as cheese, wine, and baked goods. It reacts with potassium to make potassium sorbate, and with calcium to make calcium sorbate, both of which are used as antifungals.

Why There's Antifreeze in Your Toothpaste

Nalamycin

Chemical Formula

C33H47N013

HO

NH2

"o-O-··-OH o \

OH

H ----

OH

O~

0 ~

OH

Synonyms

Pimaricin • natacyn

Description

White powder.

Uses

Natamycin is a fungicide used to keep cheese from getting moldy. It works by making holes in the cell membranes of fungi, so their insides leak out. It is produced by Streptomyces natalensis bacteria. It is applied to cut slices of cheese by dipping or spraying. Some manufacturers use it in the wax coating on cheese rinds instead of on the cheese itself. In grated cheese, a dry mixture is used, usually with cellulose to prevent caking.

Preservatives

Triclosan

Chemical Formula

CI

OH

CI

Synonyms

2,4,4'-trichloro-2'-hydroxydiphenyl ether· 5-chloro-(2,4-dichlorophe- noxy)phenol· trichloro-2'-hydroxydiphenyl ether· CH-3565 • Lexol 300· Irgasan DP 200

Description

White powder.

Uses

Triclosan is a broad-spectrum antibacterial and antifungal agent. It is an ingredient in toothpastes and mouthwashes, detergents, laundry soaps, and cosmetics. It kills germs by interfering with the enzyme necessary for fatty-acid synthesis. It is related to hexachlorophene in structure.

Triclocarban

Chemical Formula

CI

II

C'-o- NH/'--. NH

Synonyms

Trichlorocarbanilide • N-(4-chlorophenyl)-N' -(3,4-dichlorophenyl) urea

Why There's Antifreeze in Your Toothpaste

Description

White crystals or powder.

Uses

Triclocarban is used as an antibacterial and antifungal agent in disin- fectants, soaps, and other household products.

Hexachlorophene

Chemical Formula

CI

OH

HO

CI

Synonyms

Hexachlorophane • hexachlorophen • hexophene • phisohex

Description

White powder.

Uses

Hexachlorophene is a broad-spectrum antibacterial agent. It is used in hospital scrubs, shampoos, and deodorants. Once widely used in over-the-counter products, hexachlorophene is now available by prescription only, due to incidents of overdose in infants in France during the 1970s. It has been largely replaced by the related compound triclosan.

Preservatives

Acetic Acid

Chemical Formula

II

~OH

Synonyms

Vinegar

Description

Sour-tasting clear liquid.

Uses

Acetic acid, in the form of vinegar, is used to preserve foods such as pickles. It also provides the sour taste for salad dressings and may- onnaise. Acetic acid is a fungicide and is used in cleaning products to remove calcium deposits left behind by hard water.

Sodium Chloride

Chemical Formula

NaCI

Synonyms

Salt

Description

White cubic crystals with a characteristic salty odor.

Uses

Salt is used as an essential nutrient and a flavoring in food. It is also used in products to change their properties. In breads, it moderates the growth of yeast, and strengthens gluten. In ice cream and frozen

Why There's Antifreeze in Your Toothpaste

foods, it lowers the freezing point of water. In cured meats, it acts as a preservative by attracting moisture out of the cells of microbes, which causes them to die. It also acts as a tenderizer by helping the proteins bind to water. It develops the color in preserved meats so they don't look gray. And by binding proteins to water it keeps sausage and other ground or chopped meats from falling apart. In shampoo, it is used to adjust the final viscosity of the product.

Focus: Table Salt

Salt has been a precious commodity throughout most of

human history. Rome's armies were paid in salt, which is the origin of the word salary. Salt is a seasoning, an essential nutrient, and a very important preservative.

Table salt is sodium chloride combined with iodine

sources (for nutrition), stabilizers for the iodine, and anti- caking compounds to prevent it from absorbing water from the air so it can pour freely.

Potassium Iodide

Potassium iodide is added as a nutrient to prevent goiter, a thy- roid problem caused by lack of iodine, and to prevent a form of mental retardation associated with iodine deficiency. A project started by the Michigan State Medical Society in 1924 promoted the addition of iodine to table salt, and by the mid-1950s three- quarters of U.S. households used only iodized salt. Potassium iodide makes up 0.06 percent to 0.01 percent of table salt by weight. Sometimes cuprous iodide-iodide of copper-is used instead as the source of iodine.

Glucose (Dextrose)

Glucose is a sugar (the main sugar in corn syrup), and is added in small amounts (0.04 percent) to salt to prevent the potassium iodide from breaking down into iodine, which would evaporate

Preservatives

29 away through sublimation. Other potassium iodide stabilizers include sodium bicarbonate (baking soda), sodium carbonate, and sodium thiosulfate.

Calcium Silicate

Calcium silicate is an anticaking additive. Salt is hygroscopic, meaning it absorbs water from the air. This water dissolves the salt, and the resulting saltwater combines with the remaining salt, cementing the grains together into a solid mass. Calcium sil- icate absorbs moisture from the air better than salt, but does not dissolve in the water it absorbs. This protects the salt from cak- ing, and ensures that it pours freely. Less than 0.5 percent is generally used, so in very humid weather, the salt may still become lumpy.

Other anticaking ingredients include ferric ammonium citrate,

silicon dioxide, sodium ferrocyanide, magnesium silicate, magne- sium carbonate, propylene glycol, aluminum calcium silicate, sodium aluminosilicate (also called sodium silicoaluminate), and calcium phosphate.

Sugars

Chemical Formula

OH

Glucose

Why There's Antifreeze in Your Toothpaste

OH

Fructose

OH

o~ '-_~ 0

OH

Sucrose

OH

~--O

OH

Galactose

OH

Preservatives

OH

Mannose

Synonyms

Dextrose· invert sugar· corn syrup· high-fructose corn syrup

Description

White crystals or powder.

Uses

Sugars are used as sweeteners, as thickeners, and as structural elements in foods (e.g., to make granola cruchy and hard candies hard). Table sugar is sucrose. It is made from two simpler sugars called glucose and fructose. Glucose is sometimes called dextrose. Glucose is a little less sweet than sucrose, and fructose is sweeter than sucrose. When sucrose is heated in the presence of an acid, such as vinegar or lemon juice, it breaks down into glucose and fructose, and the result- ing syrup is sweeter than sucrose. The syrup is called "invert sugar." Simple sugars can join to form long chains. Glucose units can

chain up to form amylose

··· .......0

Amylose

OH

Why There's Antifreeze in Your Toothpaste

the starch in corn, or cellulose

OH

0 (OH-Y

..."0 'l......("

OH

Cellulose

the molecule that forms the structure of plants. Amylose can be broken down into its simple glucose units using enzymes. The result is called corn syrup. More processing, using enzymes that convert glucose into fructose, yields high-fructose corn syrup. The mixture of glucose and fructose is similar to that in sucrose and invert sugar, and it is sweeter than plain corn syrup. There are many different types of simple sugars, and they can combine into many more types of complex sugars. The backbone of DNA is a chain made of sugars.

Focus: Sweeteners

What would life be like if nothing was sweet? There are many sweeteners available today. Some are nutritive sweeteners, such as sugar; others are non-nutritive, such as saccharin; and still others fall somewhere in between, as they may have fewer calo- ries than sugar, or be poorly metabolized in the body, or both. Here is a list of sweeteners sorted according to how sweet

they taste

Name

Neotame

Sucralose

Saccharin

Acesulfame potassium

Aspartame

Fructose

Invert sugar

High-fructose corn syrup

Xylitol

Tagatose

Maltitol

Glucose

Sorbitol

Mannitol

Maltose

Trehalose

Regular corn syrup

Lactose

% as Sweet as Sucrose (Table Sugar) 800,000 60,000 30,000 20,000 16,000 170 120 120 100 92 90 75 55 50 45 45 40 15

Preservatives

The non-nutritive sweeteners stand out because they are so

much sweeter than sugar. Sugar is a disaccharide, two simple sugars in one molecule. The two simple sugars are glucose and fructose. Glucose is not as sweet as sugar, but fructose is much sweeter. This is why high-fructose corn syrup is sweeter than sugar, and why breaking the sugars in sucrose apart into glucose and fructose (making invert sugar) results in a sweeter mixture. Adding a hydrogen or two to a sugar makes a sugar alcohol. The sugar alcohols xylitol, maltitol, sorbitol, and mannitol are all used as sweeteners in food. They are not absorbed well by the body, and they don't have as many calories as sugar. As with any

Why There's Antifreeze in Your Toothpaste

food that is not absorbed well, too much can have laxative effects. Sugar alcohols occur naturally in many foods. Our bodies create sugar alcohols as a normal part of metabolism. They are similar to sugar in their properties, so they can be used like sugar in cooking. Variations in their hygroscopicity (ability to absorb water from the air), their melting points, and their reac- tions with other ingredients determine which should be used in a particular recipe. Sugar alcohols do not brown like sugar, and so they are used when caramelized brown color is not desired.

Disaccharides like maltose, lactose, and trehalose are used

for their similarity to sucrose, but with differences in some prop- erties, such as sweetness, melting point, or hygroscopicity.

Calcium Propionate

Chemical Formula

II

~O::ca ~O

IIo

Synonyms

Calcium propanoate

Description

White crystalline solid or powder.

Preservatives

Uses

Calcium propionate is used in bakery products as a mold inhibitor. Propionates prevent microbes from producing the energy they need, just as benzoates do. However, unlike benzoates, propionates do not require an acidic environment. Sodium propionate is also often used as an antifungal agent. Cal- cium is often preferable to sodium, both to reduce sodium levels in the diet and because calcium ions are necessary for the enzyme a- amylase to act on the starches in bread, making them available for the yeast, and improving the texture of the bread. Stale bread is caused by the starch amylose recrystallizing. The enzyme a-amylase converts some of this starch to sugars, which helps prevent recrystallization.

Sodium Propionate

Chemical Formula

II

~O-Na

Synonyms

Sodium propanoate

Description

White crystalline solid or powder.

Uses

Sodium propionate is used in bakery products as a mold inhibitor. Like benzoates, propionates prevent microbes from producing the energy they need. However, unlike benzoates, propionates do not require an acidic environment. Calcium propionate is often preferred as an antifungal agent, to reduce sodium levels in the diet, but also because calcium ions are necessary for the enzyme a-amylase to act on the starches in bread,

Why There's Antifreeze in Your Toothpaste

making them available for the yeast, and improving the texture of the bread. Stale bread is caused by the starch amylose recrystallizing. The enzyme Imidazolidinyl Urea

Chemical Formula

Description

White powder. Highly soluble, hygroscopic.

Uses

Imidazolidinyl urea kills gram-negative bacteria. It acts synergistically with parabens to provide a broad-spectrum antibiotic that is effective against mold, yeast, and bacteria. The combination of the two chem- icals constitutes the most widely used preservative in cosmetics.

Imidazolidinyl urea works by releasing formaldehyde into the

product, just like the related preservative OMOM hydantoin.

Preservatives

Methyl Paraben

Chemical Formula

OH

0=== 0-

Synonyms

Methyl4-hydroxybenzoate

Description

Colorless crystals or white powder.

Uses

Parabens are phytoestrogens found in plants such as blueberries; they are used as preservatives in food, cosmetics, sunscreens, shampoos, and many other products. Parabens kill molds and fungi. They are used synergistically with bactericides to make broad-spectrum antimicrobials.

Related Compounds

OH

0=== O~

Ethyl paraben

Why There's Antifreeze in Your Toothpaste

OH

Propyl paraben

0== O~

Isothiazolinone

Methylisothiazolinone

Methylchloroisothiazolinone

Chemical Formula

C21 H38NCI

CI

b~o

Preservatives

Synonyms

2-methyl-4-isothiazolin-3-one (MI) • 5-chloro-2-methyl-4-isothia- zolin-3-one (MCI) • kathon

Description

Amber liquid.

Uses

Isothiazolinones are a class of broad-spectrum biocides used as preservatives in many household and industrial products. They are used in cosmetics and shampoos as a biocide to kill fungi and bacte- ria. Unlike the preservatives DMDM hydantoin and imidazolidinyl urea, also commonly used in these products, isothiazolinones do not release formaldehyde, to which some people are sensitive. On the other hand, some people are sensitive to isothiazolinones. lactic Acid

Chemical Formula

CH 3CH(OH)COOH

o >- OH

HO

Synonyms

2-hydroxypropanoic acid· alpha-hydroxypropionic acid· I-hydroxy- ethanecarboxylic acid· ethylidenelactic acid

Description

Colorless or slightly yellow syrupy liquid.

Uses

Lactic acid is what gives the sour taste to spoiled milk and to sauer- kraut. It is used in foods to add tartness, and to preserve freshness in

Why There's Antifreeze in Your Toothpaste

foods such as Spanish olives. Though the name comes from the Latin word for milk, most lactic acid is produced commercially from corn fermentation.

Sodium Nitrite

Chemical Formula

NaNOz

Synonyms

Nitrous acid sodium salt

Description

White or yellowish powder.

Uses

Sodium nitrite is used to fix the colors in preserved fish and meats. It is also important (along with sodium chloride) in controlling the bac- terium Clostridium botulinum, which causes botulism. Lunch meats, hams, sausages, hot dogs, and bacon are usually preserved this way. In medicines, it is a vasodilator, intestinal relaxant, bronchodila- tor, and an antidote to cyanide and hydrogen sulfide poisoning. Sodium nitrite is produced in the human body by the action of saliva on sodium nitrate, and is important in controlling bacteria in the stomach, to prevent gastroenteritis. The body produces more sodium nitrite than is consumed in food. Sodium nitrite can react with proteins in the stomach or during cooking, especially in high heat (such as frying bacon), to form car- cinogenic N-nitrosamines. To prevent this, ascorbic acid or erythor- bic acid is commonly added to cured meats.

Preservatives

41 During the curing process, some of the nitrites are converted to nitric oxide. This combines with the myoglobin proteins in the muscle of the meat to form the deep red nitric oxide myoglobin, which causes cured meats such as ham to turn pink during the smoking process. Nitrites prevent foods from getting rancid by preventing the for- mation oftoxic maldonadehyde, which is formed as foods get rancid.

Sodium Nitrate

Chemical Formula

NaN03

o 0 "'" /

Na+

Synonyms

Soda nitre· chile saltpeter· sodium saltpeter· nitratine • nitric acid sodium salt

Description

White crystals.

Uses

Sodium nitrate has been used for centuries to cure meat. Bacterial action during curing converts the sodium nitrate into sodium nitrite, which kills the bacteria that cause botulism, and combines with the myoglobin in the meat to form the pink color associated with ham. These days, sodium nitrite replaces most of the sodium nitrate used in cured meats, except for that used in slow-cured country ham.

Why There's Antifreeze in Your Toothpaste

DMDM Hydantoin

Chemical Formula

/---NY ~o

HO

LI

o >

HO

Synonyms

1,3-bis(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione

Description

Clear liquid.

DMDM hydantoin is a preservative that works by releasing

formaldehyde into the product.

Uses

DMDM hydantoin is used in shampoos and cosmetics to prevent

molds, mildews, and bacterial spoilage.

Another formaldehyde-releasing preservative is imidazolidinyl

urea (see page 36).

Glycols

Chemical Formulas

~OH

HO

Ethylene glycol

OH

~OH

Propylene glycol

Preservatives

43 rY'"

OH

Bulylene glycol

Synonyms

Ethylene glycol: ethanediol • dihydroxyethane

Propylene glycol: propanediol • dihydroxypropane

Butylene glycol: butanediol • dihydroxybutane

Description

Clear liquids.

Uses

Ethylene glycol is common in automotive antifreeze mixtures. Because of its toxicity, it is sometimes replaced by propylene glycol, which is FDA approved for use in food, and is considered "generally accepted as safe." Ethylene glycol has a sweet taste, and accidental poisoning in children is a danger. Propylene glycol and butylene glycol are often used as humectants (moisturizers) as they are hygroscopic (they draw moisture from the air). Propylene glycol is what is used in artificial smoke or fog machines. It is also used as a preservative. 2-bromo-2-nitropropane-1,3-diol

Chemical Formula

Sr

HO~OH

0/ ""0

Synonyms

Bactrinol-IOO • b-bromo-b-nitrotrimethyleneglycol

Why There's Antifreeze in Your Toothpaste

Description

White to pale yellow crystalline powder.

Uses

This ingredient is a bactericide used in sunscreens, hair conditioners, paints, disinfectants, and water-treatment plants.

Buffers

2 Some chemicals have a very nice property of maintaining the pH of a substance they are added to. If the substance becomes more acidic, the buffer ingredient shows its alkaline side and neutralizes the acid. If the substance becomes more alkaline, the acid side of the buffer neutralizes it.

Sodium Citrate

See entry, page 19.

Aminomethyl Propanol

Chemical Formula

Synonyms

AMP

0 AMP-95

0 2-amino-2-methyl-1-propanol o isobutanolamine 0 amino-2-methylpropanol o hydroxymethyl-2-propylamine 45

Why There's Antifreeze in Your Toothpaste

Description

Colorless or slightly yellow combustible liquid.

Uses

AMP is used as an emulsifier and a buffering agent. It controls the water solubility of the resin film in hairsprays, and makes the finished film more resistant to humidity. AMP forms a gel with long-chain acrylic polymers.

Tetrasodium Pyrophosphate

Chemical Formula

Na40 7P2

Synonyms

Sodium pyrophosphate· TSPP • tetrasodium diphosphate

Description

Colorless transparent crystals or white powder.

Uses

Tetrasodium pyrophosphate is used as a pH buffer (a substance that maintains a particular acidity level), and as a dough conditioner in soy-based meat alternatives.

It promotes binding of proteins to water, binding the soy particles together, and is used for the same purpose in chicken nuggets and imitation crab and lobster products.

It is an emulsifier, and a source of phosphorus as a nutrient.

It also is used in toothpastes, as a buffer, an emulsifier, and a deter- gent aid.

It is the "tartar control" agent.

It removes calcium and mag- nesium from the saliva, so they can't deposit on the teeth.

It is a thickening agent in instant puddings.

It is a water softener in detergents, and an emulsifier to suspend oils and prevent them from redepositing on clothing in the wash.

As a water softener, it combines with magnesium to sequester it from the detergent and keep it from precipitating onto clothing.

Buffers

47 As a detergent additive, it can also reactivate detergents or soaps that have combined with calcium to make an insoluble scum. The TSPP sequesters the calcium, replacing it with sodium, which reacti- vates the detergent or soap, and yet keeps the calcium from precipi- tating out of solution.

Because phosphates cause eutrophication of water (algae grow

because of the fertilizing power of phosphates), it is seldom used as a detergent additive except in toothpastes.

Phosphoric Acid

Chemical Formula

H3P04

Description

White solid.

Uses

Phosphoric acid is used in soft drinks, jams, jellies, and cheeses to add a tart (acid) flavor.

The sodium

salt of phosphoric acid, sodium phosphate (NaH 2P04), is weakly acidic, and is used with sodium bicarbonate to make baking powders. Other acids used in baking powder are fumaric acid and tartaric acid.

Chelating or

Sequestering Agents

(Water Softeners) 3 The word chelating comes from the Latin word for claws, chelae, like the claws of a crab. A chelating agent grabs on to another molecule, like a crab's claw, and prevents it from reacting with other molecules. Chelating (sometimes called sequestering) agents include water- softening agents that lock up the calcium and magnesium in hard water so that they don't interfere with soaps and detergents. Other chelating agents are added to foods to lock up metals, such as nickel and copper, to prevent them from reacting, or as a medicine to remove mercury or other toxic heavy metals from the body.

Ethylene Diamine Tetra Acetic Acid

Chemical Formula

o 0

HO

II

OH

1 r

N~N

Na-o~

o -

Na

II

o 0

Sodium EDTA

Why There's Antifreeze in Your Toothpaste

Synonyms

Sodium EDTA· calcium EDTA

Description

White crystalline powder.

Uses

Sodium or calcium EDTA binds to metals, such as nickel, copper, and iron, making them unavailable to react with other ingredients in a product, or with compounds in the human body.

EDTA sequesters calcium and magnesium from hard water, pre-

venting them from forming insoluble soap films (scum) with soaps and detergents. Chelators are sometimes used to sequester metal ions that interfere with dyes and perfumes. EDTA also is used to treat lead and mercury poisoning, as it can lock up those metals so they can do no harm in the body.

Compounds with similar functions are sodium carbonate, pen-

tasodium pentetate, sodium citrate, phosphoric acid, tetrasodium etidronate, and tetrasodium pyrophosphate.

Diethylene Triamine Pentaacetic Acid

Chemical Formula

NaO

O-;:::::::"(~

O~(

NaO

~o o \ ./"'-- NaO

)-:::=-0

NaO

"'-H

Chelating or Sequestering Agents (Water Softeners)

Synonyms

Pentasodium pentetate • (( (carboxymethyl)imino)bis(ethyleneni- trilo) )tetraacetic acid· pentasodium salt

Description

White crystals. Diethylene triamine pentaacetic acid is a chelating agent that sequesters metal ions so they cannot combine with other ingredients in a product.

Uses

Diethylene triamine pentaacetic acid is used in soaps as a water sof- tener, and to protect dyes and perfumes from combining with metals in solution.

Compounds with similar functions are sodium carbonate,

sodium EDTA, sodium citrate, phosphoric acid, tetrasodium etidronate, and tetrasodium pyrophosphate.

Phosphoric Acid

See entry, page 47.

Sodium Citrate

See entry, page 19.

Tetrasodium Pyrophosphate

See entry, page 46.

Why There's Antifreeze in Your Toothpaste

Tetrasodium Etidronate

Chemical Formula

NaO

II

""p /

NaO

oII/oNa c-p

~ONa

OH

Synonyms

Tetrasodium (l-hydroxyethylidene) bisphosphonate

Description

Clear or pale yellow liquid.

Tetrasodium etidronate, and the related disodium etidronate,

HO

II

""p /

NaO

II/

OH

C-p

~ONa

OH

are chelating agents and sequestering agents that attach to metal ions to keep them from reacting with other compounds in a mixture, and to prevent them from precipitating out of solution as insoluble scums.

Uses

Tetrasodium etidronate is used as a water softener in soaps to prevent soap scum and bathtub rings by locking up the calcium and magne- sium in the water.

Compounds with similar functions are sodium carbonate,

sodium EDTA, sodium citrate, phosphoric acid, and tetrasodium pyrophosphate.

Chelating or Sequestering Agents (Water Softeners)

Sodium Carbonate

Chemical Formula

Na2C03

Synonyms

Soda· soda ash· washing soda

Description

White hygroscopic powder or crystals.

Uses

Sodium carbonate is used in detergent formulas as a water softener, to lock up calcium and magnesium from the water. Calcium and mag- nesium would otherwise combine with the soap or detergents and form an insoluble scum that would stick to the clothes and the wash- ing machine.

Compounds with similar functions are pentasodium pentetate,

sodium EDTA, sodium citrate, phosphoric acid, tetrasodium etidron- ate, and tetrasodium pyrophosphate.

Alcohols and Phenols 4

This group of ingredients has many useful properties. Alcohols and phenols are very common in household products. Alcohols are good solvents and are used in perfumes and flavorings to dissolve fats and oils. Heavier alcohols with long chains of hydrocarbons act as emul- sifiers and surfactants, bringing oil and water together.

Ethanol

Chemical Formula

~OH

Synonyms

Alcohol· ethyl alcohol· SO alcohol 40-B

Description

Colorless flammable liquid.

Uses

When the word alcohol is used alone, it refers to ethanol, the alcohol found in wine, beer, and distilled spirits. Ethanol is used as a fast-dry- ing solvent in many products, especially cosmetics and hairsprays. 55

Why There's Antifreeze in Your Toothpaste

When used in products not licensed for drinking, ethanol usually occurs in the form of denatured alcohol, or "specially denatured" alco- hol-alcohol that has been rendered unfit for drinking. You will often see "SD alcohol" mentioned on a label, sometimes followed by a num- ber and letter, such as "40-B." This is the designation given by the u.s. Bureau of Alcohol, Tobacco, and Firearms to the denaturing method used. For example, SD-40 is ethanol denatured by adding tiny amounts of the most bitter-tasting substance known: denatonium benzoate.

Other Alcohols

There are a large number of alcohols besides ethanol. All of them have the hydroxyl group OH attached to a carbon atom. The simplest is

methanol

H-C-OH

Methanol has one carbon, ethanol has two, and there are two forms of the alcohol that contain three carbons: propanol ~OH and isopropanol

OH

Stearyl Alcohol

Chemical Formula

OH

Alcohols and Phenols

Synonyms

l-octadecanol • octadecyl alcohol

Description

White solid or flakes.

Uses

Stearyl alcohol is a nonionic surfactant used as a hair coating in sham- poos and conditioners. Stearyl alcohol also is used as an emollient (skin softener), emul- sifier, and thickener in creams and lotions.

Cetyl Alcohol

Chemical Formula

OH

Synonyms

I-hexadecanol • hexadecyl alcohol

Description

White solid or flakes.

Uses

Cetyl alcohol is a nonionic surfactant used as a hair coating in sham- poos and conditioners. It is used as a water-based lubricant for fasteners, such as nuts and bolts. It is used as an emollient (skin softener), emulsifier, and thickener in creams and lotions.

Why There's Antifreeze in Your Toothpaste

Glycerin

Chemical Formula

HOI

HOl

HO

Synonyms

Glycerol· glycerine· 1,2,3 trihydroxy propane· 1,2,3 propanetriol

Description

Glycerin is a clear, sweet-tasting, somewhat viscous oily liquid. It is manufactured from petroleum, or from glycerides in fats, often as a by-product in the production of soap.

Uses

Glycerin is hydrophilic (water-loving), and is used to keep products such as dried fruits from getting too dry, and to keep the liquid in soft fillings from escaping into crisp crusts, making them soggy. This emollient (moisturizing) effect also finds use in hand creams. It low- ers the freezing point of water, and is used as an antifreeze. Glycerin is about three-quarters as sweet as sugar, so it can reduce the need for sugar in products that require it for other reasons. In toothpaste it sweetens while keeping the paste from drying out when the cap is left off. Glycerin is used in many skin creams and medicines, such as eye and ear drops, poison ivy creams, suppositories, and contraceptive jel- lies. It is also used as an emollient (skin softener) in soaps. When glycerin reacts with nitric acid in the presence of sulfuric

acid (as a drying agent) a familiar compound results

Alcohols and Phenols

59 0 ........

0/ '0

Glyceryl trinitrate

Glyceryl trinitrate is used in medicines for its effects on blood flow. Physicians use it as a coronary vasodilator for their heart patients. As an explosive, glycerin is the principle ingredient in dynamite, under the name nitroglycerin.

Menthol

Chemical Formula

Synonyms

2-isopropyl-5-methyl-cyclohexanol

OH

Why There's Antifreeze in Your Toothpaste

Description

Colorless crystals with a strong characteristic odor. It is the chief con- stituent of peppermint oil.

Uses

Menthol is a mild anesthetic and anti-irritant. It causes a cool sen- sation on the skin, by activating the peripheral cold receptors. It is used in cigarettes, and in topical creams for the relief of sore mus- cles. It also is used in cough drops, aftershave lotions, inhalers, and cooling gels. Menthol is used as a flavoring in toothpastes, chewing gums, can- dies, and liquors. And it is used as a perfume in towels, handkerchiefs, deodorizers, and shampoos.

Waxes

Although some waxes are made from more complicated building

blocks, most of what are commonly called waxes are esters. In addi- tion to the uses discussed below, waxes were used for many years to make candles; today, however, most candles are made from long-chain hydrocarbons called paraffin, which are not true waxes.

Esters

Chemical Formula

Synonyms

Beeswax (triacontanyl palmitate) • octadecyl octadecanoate (stearyl stearate) • dodecyl hexadecanoate (lauryl palmitate) • cetyl palmitate • lanolin· carnauba wax· glycol distearate • jojoba oil 61

Why There's Antifreeze in Your Toothpaste

Description

Waxy solids, combinations of long-chain alcohols and long-chain fatty acids. The wax that bees make is a complicated mixture of many com- pounds, but about 70 percent of it is the wax made from palmitic acid, a fatty acid, and the long-chain alcohol triacontanol (melissyl alcohol).

Uses

Waxes are used in water-resistant coating on cars and furniture. They are also used in lipsticks and eyebrow pencils and in liquid soaps and shampoos to give a pearlescent effect (the tiny flakes of the wax gly- col distearate reflect the light). Lanolin is a wax made in the sebaceous glands of sheep and washed out of wool with detergents. It is used in many hair- and skin- care products. Waxes are the principal component in traditional varnishes such as shellac, a wax made by the cochineal insect Tachardia lacca.

Flavorings

6 Flavorings can be derived from simple acids that add a sour taste to foods, or they can comprise more complex molecules, such as dena- tonium benzoate, which is added to products to make them so bitter that no one will accidentally ingest harmful amounts.

Acids

Acetic Acid

See entry, page 27.

Citric Acid

Chemical Formula

O~

OH

HO

OH

Why There's Antifreeze in Your Toothpaste

Synonyms

2-hydroxy-l ,2,3-propanetricarboxylic acid

Description

Colorless, odorless, translucent crystals or powder. Strongly sour (acidic) taste.

Uses

Citric acid is used as a food additive to make foods tart, to adjust the acidity, or to mix with bicarbonates to generate carbon dioxide gas. It is also used known for its antioxidant properties, and can be used to prevent oils from becoming rancid. Citric acid is also highly astringent; it can be used as a skin toner. Like the related compound sodium citrate, citric acid is often an ingredient in ice creams, where it helps keep the fat globules separate.

Lactic Acid

See entry, page 39.

Stearic Acid

Chemical Formula

CH3(CH2)16COOH

II

OH

Synonyms

I-heptadecanecarboxylic acid· n-octadecanoate • n-octadecylic acid • cetylacetic acid· stearophanic acid

Description

White or yellowish solid.

Flavorings

Uses

Stearic acid is the most common of the long-chain fatty acids.

It is found in many foods, such as beef fat and cocoa butter.

It is widely used as a lubricant in soaps, cosmetics, food packaging, deodorant sticks, and toothpastes.

It is also a commonly used softener in rubber. ~ Chemistry Lesson Stearic acid is a member of the group called fatty acids.

These are hydrocarbon chains (chains made of repeated units of a carbon atom and two hydrogen atoms) with a carboxyl group at one end.

A car- boxyl group is the COOH in the chemical formula.

It is what turns the hydrocarbon chain into an organic acid.

The carboxyl group in organic acids is reactive, and will easily lose its hydrogen to a compound that has a hydroxyl group, which is an oxygen atom joined to a hydrogen atom (OH).

The H from the car- boxyl group joins the OH of the hydroxyl group, and the two become HOH, more commonly known as H20: water.

The water leaves as a separate molecule, and the two original molecules become joined at the point where the carboxyl and hydroxyl groups were.

One compound, glycerol, happens to have three hydroxyl groups.

Glycerol can combine with fatty acids to form compounds called glycerides.

If there is one fatty acid, you get a monoglyceride.

If there are two fatty acids, you get a diglyceride.

When there are three fatty acids, you get a triglyceride.

Glycerol stearate is a monoglyceride.

It is glycerol attached to stearic acid.

Because it still has two free hydroxyl groups attached to the glycerol, that portion of the molecule is hydrophilic, or attracted to water.

The long hydrocarbon chain of the stearic acid is hydropho- bic, or attracted to oils and fats instead of water.

This makes it a good emulsifying agent and surfactant.

An emulsifier helps to mix oil and water in products such as mayonnaise and butter.

Diglycerides are also emulsifying agents.

You will see mono- and diglycerides as ingredients in many foods that combine oil and water.

Why There's Antifreeze in Your Toothpaste

Triglycerides are fats. The fats in butter and bacon, like the fats in your body, are made of triglycerides. Stearic acid is a saturated fatty acid. This means it has only single bonds between its carbon atoms. This means it can coil up and form into random shapes. Double bonds between carbon atoms restrict the bending of the molecule at the point of the bond, like a hinge that lets a door swing back and forth but not up and down. Triple bonds are even more restrictive, locking the joint in place three-dimensionally, like the legs of a tripod. Unlike most saturated fats, stearic acid does not seem to increase cholesterol levels in the blood. This is because liver enzymes convert it to an unsaturated fat during digestion.

Phosphoric Acid

See entry, page 47.

Fumaric Acid

Chemical Formula

Synonyms

Allomaleic acid· 2-butenedioic acid· trans-butenedioic acid· boletic acid· lichenic acid· trans-l ,2-ethenedicarboxylic acid

Description

Colorless crystals or white powder.

Uses

Fumaric acid is used as a flavoring, because it is the sourest tasting of the organic acids. Three parts of fumaric acid are as sour as five parts of citric acid.

Flavorings

67 It is also used as an antioxidant, as a mordant (a substance that helps dyes stick to fabric), and as a buffering agent (which helps main- tain a particular acidity or alkalinity).

Fumaric acid is used to lower the pH (make something more acidic, which makes it taste more sour).

This helps certain antimi- crobial agents such as sodium benzoate and calcium propionate work more effectively.

Fumaric acid also kills bacteria.

Fumaric acid breaks the sulfur-to-sulfur bonds in the elastic pro- tein gluten in bread doughs.

This makes the doughs more machine- able.

It also is a key ingredient in rye and sourdough breads-it makes them sourer.

Fumaric acid is used in combination with sodium bicarbonate to create delayed-action leavening agents (something that produces car- bon dioxide gas to make breads rise).

Since it only dissolves in warm water, the leavening action is delayed until the bread starts to bake.

Because fumaric acid is not very soluble in water, it can replace hygroscopic acids in dry mixes, and thus help keep them from caking in humid conditions.

Tartaric Acid

Chemical Formula

HO

HO, ~ Jl

If I

'OH o

OH

Synonyms

2,3-dihydroxybutanedioic acid

Description

White powder. Tartaric acid is the molecule that makes unripe grapes taste sour. It is a principal flavor element in wine.

Why There's Antifreeze in Your Toothpaste

Uses

Tartaric acid is used as a flavoring agent to make foods taste sour. The potassium salt oftartaric acid, potassium bitartrate or potas- sium hydrogen tartrate, is weakly acidic, and is known as cream oftar- tar. Since it is a dry acid, cream of tartar is used in baking powders (along with sodium bicarbonate) to produce carbon dioxide gas when added to water. Other acids used in baking powder are fumaric acid and phosphoric acid.

Esters

Methyl Vanillin

Chemical Formula

HO

Synonyms

Vanillin'3-methoxy-4-hydroxybenzaldehyde

Description

White to light yellow crystalline powder.

Uses

Methyl vanillin is used in flavorings, fragrances, pharmaceuticals, and perfumes. It is closely related to ethyl vanillin, a slightly larger molecule. Because it does not have quite the same taste as the much more complex mixture of compounds found in natural vanilla extract, it is most often used with stronger flavors and scents such as chocolate, cloves, nutmeg, or cinnamon.

Flavorings

Ethyl Vanillin

Chemical Formula

HO

Synonyms

3-ethoxy-4-hydroxybenzaldehyde

Description

White to pale yellow powder or crystals with a characteristic odor of vanilla.

Uses

Ethyl vanillin is a synthetic compound that is three and a half times stronger in flavor than real vanilla, although the flavor is not guite the same. Because it is less expensive and keeps better during storage and transport, ethyl vanillin is used as a substitute for vanilla in foods and perfumes. It is closely related to the slightly smaller molecule methyl vanillin.

Denatonium Benzoate

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

Bitrex

Description

White crystalline powder with an extremely bitter taste.

Uses

Oenatonium benzoate is the bitterest-tasting substance known. It gets its name from denatured alcohol-alcohol that has been rendered unfit for drinking-and is often used in the denaturing process. Spe- cially denatured alcohol 40, or SO-40, is ethanol that has been dena- tured by a tiny amount ofdenatonium benzoate. Oenatonium benzoate is an ester of PABA, and is related to lidocaine, benzocaine, novocaine, and cocaine. It is used in deer repellant, nail polish (to discourage nail-biting), paint, antifreeze, and windshield washing fluid (to prevent accidental ingestion), and to coat electrical cables (to prevent rats or other ver- min from eating the insulation). Very dilute solutions are sometimes used to coat children's thumbs to prevent thumb sucking.

Other Flavorings

Vanilla

Chemical Formula

Vanilla is a complex mix of many compounds, such as vanillin and related esters.

Synonyms

Vanilla beans· vanilla sugar· vanilla extract

Description

Long black bean. Vanilla is sold in many forms, such as the vanilla bean, vanilla extract, and vanilla sugar. The vanilla bean is the fruit of the orchid Vanilla planifolia, a native of Mexico, but now grown in many tropical countries such as Madagascar, Tahiti, and Java. The flowers of the vanilla orchid are pol-

Flavorings

71 linated by local Mexican bees and hummingbirds, and until a hand pollination method was developed, the seed capsules could only be farmed in Mexico.

Orchid flowers bloom once per day, and a good hand pollinator can pollinate one thousand to two thousand plants a day.

The seeds ripen about nine months after they are pollinated.

The seed pods are picked when they turn yellow, and dried in the sun during the day, then placed in straw or blankets in airtight boxes to "sweat" and ferment overnight.

The sun drying, boxing, and fer- menting process is repeated many times for over a month, and the result is black seed pods that are then thoroughly dried, boxed, and cured for a few months before being shipped.

The long fermenting process converts several glucosides into glu- cose, vanillin, and other complex aromatic flavors.

The vanilla beans can be further processed by extracting soluble compounds in ethanol and water mixtures, resulting in vanilla extract.

Uses

Vanilla is used in many products, usually sweetened foods, and scented products, such as perfumes and candles. Vanilla grown in one location tastes different than that grown in another location, much like coffee, wine, and chocolate. Many con- fectioners claim the vanilla grown in Madagascar, known as Bourbon Vanilla, tastes the best, because of its fruity "top note." The vanilla grown in Indonesia has a simpler flavor and is used in baking, where any top notes would be removed from the product by the high heat. Mexican vanillas are often described as "spicy." Tahitian vanilla is said to have flowery, soft flavors, resembling root beer, which is a some- what circular reference, since most root beer contains vanilla. There are also blended vanillas, mixing beans from various locations.

Monosodium Glutamate

Chemical Formula

H .......... /H

Na+-O~OH

II

o 0

Why There's Antifreeze in Your Toothpaste

Synonyms

Sodium glutamate· MSG • I-glutamic acid· monosodium salt •

hydrolyzed vegetable protein· utolyzed yeast· whey protein

Description

White crystalline powder.

MSG is the sodium salt of the amino acid glutamic acid.

It is made commercially by the fermentation of molasses, but exists in many products made from fermented proteins, such as soy sauce and hydrolyzed vegetable protein.

The human tongue is sensitive to five flavors: salty, sweet, bitter, sour, and umami, the taste of MSG.

Glutamic acid is a component of many proteins, such as those in dairy products, meat, legumes, and mushrooms.

However, only the free form of glutamic acid or glutamates has an effect on the gluta- mate receptors.

When bound to other amino acids in a protein, it does not stimulate glutamate receptors.

Free glutamates exist in certain cheeses (such as parmesan), in tomato products, and in soy sauce.

These products are often used to enhance the flavor of meat dishes.

Proteins can be hydrolyzed by heat, releasing free glutamates.

Cooked meats, especially grilled meats, get some of their taste from free glutamates.

Uses

MSG is used to give a meaty, savory, or brothy taste to foods by stim- ulating the glutamate receptors on the tongue. There are glutamate receptors in other parts of the body, notably the brain, where gluta- mate is a neurotransmitter. Glutamates can be produced by fermentation of starches or sug- ars, but also by breaking the bonds between amino acids in proteins, leaving free amino acids. This process is done by heat or by enzymes; it is called hydrolyzing, because the bonds are broken by adding water.

When proteins are broken down into their constituent amino

acids, the result can contain as much as 20 percent glutamates. This is why hydrolyzed vegetable protein is often listed as an ingredient in foods, to give them a meaty or savory flavor.

Flavorings

73 There is evidence that some people are sensitive to free gluta- mates. These people get headaches or other symptoms if they ingest too much. This may be related to pyridoxine (vitamin B6) deficien- cies, as this vitamin is necessary for glutamate metabolism. People with uncontrolled severe asthma may find that glutamates complicate or worsen their symptoms. Bound glutamates in proteins are very common in food. Human breast milk contains ten times as much as cow's milk, and tomato juice contains four times as much as breast milk. However, free glutamate, as found in soy sauce or prepared foods, enters the bloodstream much faster than the glutamates bound in proteins, which are released slowly during digestion.

Sweeteners

7 Sweeteners can be anything from simple sugars to fragments of pro- teins, such as aspartame, that trigger the sweet receptors on our tongues, sometimes up to two hundred times as strongly as sugar itself. Most sweeteners are forms of sugar, since sugar is very cheap and easily available. But for health reasons, more and more people are get- ting their sweeteners in non-nutritive form, or in the form of short proteins that are so sweet that the number of calories needed to sweeten the food is negligible.

Sucrose

See Sugars entry, page 29.

Invert Sugar

See Sugars entry, page 29.

Fructose

See Sugars entry, page 29. 75

Why There's Antifreeze in Your Toothpaste

High-Fructose Corn Syrup

See Sugars entry, page 29.

Neotame

Chemical Formula

\ o 0 f ~

HO

0- NH

~ ~ H

Synonyms

N-[N-(3,3-dimethylbutyl)-L-a-aspartyl]-L-phenylalanine I-methyl ester

Description

White powder. Neotame is an artificial sweetener designed to overcome some of the problems with aspartame. The dimethylbutyl part of the mole- cule was added to block the action of peptidases, enzymes that break the peptide bond between the two amino acids aspartic acid and phenylalanine. This reduces the availability of phenylalanine, elimi- nating the need for a warning on labels directed at people who can- not properly metabolize phenylalanine. Neotame does not break down with the heat of cooking, another drawback to aspartame. It is also thirty times sweeter than aspartame, so less is needed to sweeten a product.

Uses

Neotame is about eight thousand times sweeter than sugar, so only 6 milligrams is needed to sweeten a typical I2-ounce soft drink.

Sweeteners

77 Neotame is used in tabletop sweeteners, frozen desserts, chewing gum, candy, baked goods, fruit spreads, and ready-to-eat cereals.

Acesulfame Potassium

Chemical Formula

Synonyms

Acesulfame K

Description

Crystalline powder. Acesulfame potassium is a noncaloric sweetener that is two hun- dred times sweeter than sugar. It is used in tabletop sweeteners, tooth- pastes, soft drinks, desserts, baked goods, and canned foods.

Uses

Acesulfame potassium is used with other sweeteners such as aspar- tame because it has a long shelf life, and tastes sweet right away. It also has a synergistic effect with other sweeteners, so less of each is neces- sary to achieve the same sweetness.

Aspartame

Chemical Formula

II

Why There's Antifreeze in Your Toothpaste

Synonyms

L-alpha-aspartyl-L-phenylalanine methyl ester

Description

White powder. Aspartame is made from two amino acids and methanol. When it is digested, it breaks down into these three parts. Amino acids are the normal breakdown products of proteins.

Uses

Aspartame is a low-calorie sweetener used in many foods and drinks. Because it is between 160 and 200 times sweeter than sugar, only very small amounts are needed to sweeten a product. A typical 12-ounce low-calorie soft drink will have 180 milligrams of aspartame in it. In acidic solutions at high temperatures, aspartame degrades and loses its sweetness.

Sucralose

Chemical Formula

Synonyms

Splenda

Description

White crystalline powder.

OH

CI

Sweeteners

Focus: Soft Drinks

Soft drinks are among the most recognized products of

Western culture. Beginning as tonics for fatigue (and anything else that might be the matter with a patient), ~ they have evolved into sweet bUbbly accompaniments ~ to hamburgers, fries, and other fast foods.

Most soft drinks are characterized by carbonated water,

sugar, and caffeine. Variations in soft drinks generally advertise either flavor differences, or the absence of one or more of the three main ingredients.

Colas

The largest segment of the soft drink industry is cola. Colas were originally blends of extracts of the coca leaf and the cola nut, mixed with sugar water. The coca leaf is no longer used, but the cola nut remains in the recipes that are public and reportedly is also still in the secret Coca-Cola recipe. The cola nut comes from the Ivory Coast in West Africa, primarily from two species of trees, Cola acuminata and Cola nitida. The main active ingredi- ents in the cola nut are the alkaloids caffeine and theobromine ("food of the gods").

Colas stimulate digestive juices, and carbonated water

speeds the digestion, and this combination of effects, along with the stimulant action of the two alkaloids, can make a big differ- ence to someone who is not feeling well.

Sweeteners

Sugar in soft drinks has been largely replaced by high-fructose corn syrup, largely because, unlike sugar, high-fructose corn syrup is not price-controlled by the U.S. government, and because it is a bit sweeter than sugar, so less is needed.

The artificial sweetener aspartame is the low-calorie sweet-

ener of choice at the time of this writing, having replaced eyela-

Why There's Antifreeze in Your Toothpaste

mates and saccharin as the industry favorites. The sweeteners neotame, acesulfame, and sucralose are sometimes used as well.

Flavors

Acids are added to soft drinks for extra bite. The primary acid used in colas is phosphoric acid, while the one used in citrus-fla- vored drinks is usually citric acid. Carbonated water (water that has the gas carbon dioxide dissolved in it under pressure) is also mildly acidic (it is chemically carbonic acid, H2C03). Caffeine is added as a stimulant, but it has a bitter taste that is a component in many soft drinks.

Orange soda often contains glyceryl abietate, also known as

glycerol esters of wood rosin and brominated vegetable oil. These help keep fatty flavors suspended in the liquid (density balancers and emulsifiers). Gums and modified food starches are also used for this purpose. Glyceryl abietate is also used in cos- metics as the waxy substance in eyebrow pencils.

Preservatives

Sodium benzoate is used as a broad-spectrum antimicrobial,

inhibiting bacteria, molds, and yeasts. The high acid content of the soft drink is necessary for the preservative action. Sodium citrate buffers the acids, so the pH stays low (acidic). It also emulsifies any fats or fat-soluble compounds in the flavorings, keeping them in solution. Potassium sorbate is added to inhibit yeasts and fungi. Ascorbic acid (vitamin C) is used as an antioxidant.

Colors

In colas, the brown color comes from caramel coloring (burnt

sugar). Red 40 and other colors are used in fruit-flavored drinks such as orange soda.

Sweeteners

81 Sucralose is the sugar sucrose with three of the hydroxyl groups replaced by chlorine atoms. In the process, the stereochemistry of the glucose halfof the molecule is changed, making it more like galactose. Sucralose is six hundred times sweeter than sugar but has no calories.

Uses

Sucralose is used in a wide variety of no-calorie and low-calorie foods, such as tabletop sweeteners, baked goods, desserts, toothpastes, mouthwashes, and diet drinks.

Saccharin

Chemical Formula

II

~N-H

~s/ / \ o 0

Synonyms

Sweet'N Low

Description

White, sweet-tasting powder.

Uses

Saccharin is a non-nutritive sweetener used in toothpastes, cold reme- dies, ice creams, and coffee-sweetening packets. Its use in soft drinks has been almost entirely replaced by aspartame. It is about three hundred times sweeter than sugar, and passes unaltered through the body, so it has no calories.

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lactose

Chemical Formula

OH

ovFo~ ~dH

OH

Synonyms

Milk sugar

OH

Description

White, odorless, slightly sweet-tasting powder. Lactose is a disaccharide, two simple sugars in one molecule. In this case, the sugars are galactose and glucose.

Uses

Lactose is mainly used as a fermentation substrate for lactic acid bac- teria in dairy products, such as yogurt and cheese. These bacteria break down lactose into lactic acid, which solidifies the milk, and cre- ates an acid environment that favors the benign lactic acid bacteria over those that are more harmful.

Sweeteners

PoorlyAbsorbed Carbohydrates and

SugarAlcohols

Sorbitol

Chemical Formula

OH

HO

OH

Synonyms

D-glucitol • gulitol • Neosorb

Description

White, odorless, sweet-tasting powder. Sorbitol is a sugar alcohol. It has two thirds the calories of sugar, and is only 60 percent as sweet. It is poorly absorbed by the body, so it does not raise insulin levels as much as sugar. It does not promote tooth decay.

Sorbitol and mannitol are isomers, substances with the same

chemical formula but a different shape. Sorbitol can be described as a glucose molecule with two hydrogens added. The two extra hydro- gens are on either side of what used to be the double bond connect- ing the oxygen to the carbon, which is now a single bond. This changes the molecule just enough to make it harder for the body to absorb, while still allowing it to taste sweet on the tongue.

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//0

OH

HO

OH

Glucose

Sorbitol occurs naturally in fruits and vegetables. Most sorbitol in foods and other products is made from corn syrup.

Uses

Sorbitol is used in low-calorie candies and in many other foods as both a sweetener and a humectant (moisture-retaining ingredient). It also is used as an emollient (skin softener) in soaps.

Mannitol

Chemical Formula

OH

Synonyms

Manna sugar

0 mannite 0 D-mannitol o 1,2,3,4,5,6-hexanehexol

Description

White, odorless, sweet-tasting powder.

Sweeteners

85 Mannitol is a sugar alcohol. It has half the calories of sugar and is half as sweet. It is poorly absorbed by the body, so it does not raise insulin levels as much as sugar does. It does not promote tooth decay.

Mannitol and sorbitol are isomers, substances with the same

chemical formula but a different shape.

Uses

Mannitol is used as the dusty coating on chewing gum; it keeps the gum from absorbing moisture and getting sticky. This is due to its humectant (moisture-trapping) properties and very low hygroscop- icity (meaning that it does not attract moisture from the air).

Xylitol

Chemical Formula

OH

Synonyms

Wood sugar· birch sugar

Description

White, odorless, sweet-tasting powder. Xylitol is a sugar alcohol. It has 40 percent fewer calories than sugar but is just as sweet. It is poorly absorbed by the body, so it does not raise insulin levels as much as sugar does. It does not promote tooth decay.

Why There's Antifreeze in Your Toothpaste

Uses

Xylitol is used as a sweetener in many foods, including low-calorie candies, gums, and breath mints. It prevents bacteria from adhering to cells in the mouth and gums. It also binds to calcium and aids in remineralizing tooth enamel and bones. Nasal sprays and ear drops use xylitol to reduce the adhesion of bacteria.

Maltitol

Chemical Formula

OH

Synonyms

4-0-ex-D-glucopyranosyl-D-glucitol

OH

-OH

Description

White, odorless, sweet-tasting powder. Maltitol is a sugar alcohol like sorbitol, mannitol, and xylitol, but it is a larger molecule. Unlike those other sugar alcohols, and men- thol, maltitol does not stimulate the cold sensors in the skin, so it does not feel cool in the mouth.

Uses

Maltitol is used in reduced-calorie foods as a sweetener. It does not promote tooth decay, and so it is used to sweeten toothpastes and mouthwash. It is especially useful in low-calorie chocolate, because it is more like sugar than other sugar alcohols. It doesn't absorb water from the air, it is stable under heating, and it has a high melting point.

Sweeteners

Hydrogenated Starch Hydrosylate

Chemical Formula

Hydrogenated starch hydrosylate is a mixture of several polyols, or sugar alcohols, such as sorbitol, maltitol, and mannitol, among others.

Synonyms

HSH

Description

Clear viscous liquid.

Hydrogenated starch hydrosylate is made from cornstarch, potato starch, or wheat starch, which is broken down into small units such as glucose, dextrin, maltodextrin, and polydextrin, by amylase enzymes in a process called hydrolyzing.

Hydrolyzing breaks the bond between two glucose molecules by adding an OH to one glucose and a hydrogen to the other.

The Hand OH come from splitting water, hence the term hydrolyze, which means "to break apart using water." After the starch is broken into little pieces of glucose and short glu- cose chains, the pieces are converted from sugars to sugar alcohols by adding two hydrogens, using heat and pressure.

The addition of hydrogen to a molecule is called hydrogenation.

If the starch is completely hydrolyzed, so that there are only single glucose molecules, then after hydrogenation the result is sorbitol.

If the starch is not completely hydolyzed, then a mixture of sorbitol, malti- tol, and longer-chain hydrogenated saccharides (such as maltitriitol) is produced.

When there is no single dominant polyol in the mix, the compound goes by the generic name hydrogenated starch hydrosylate.

If more than half of the polyols in the mixture are of one type, then the mixture is called "sorbitol syrup" or "maltitol syrup," and so forth.

Uses

Hydrogenated starch hydrosylate is used in low-calorie candies and in many other foods as both a sweetener and a humectant (moisture- retaining ingredient).

Why There's Antifreeze in Your Toothpaste

As a crystallization modifier, it can prevent syrups from forming crystals of sugar. It is used to add body and viscosity to mixtures, and can protect against damage from freezing and drying.

Hydrogenated starch hydrosylate is also used as a carrier for

enzymes, colors, or flavors.

Salt Substitutes

8 High levels of sodium in the diet are linked to high blood pressure. Doctors often recommend that individuals who need to lower their blood pressure limit their sodium intake, but the sodium in table salt is a big part of most people's diets. They can turn to salt substitutes instead. Doctors may also recommend increasing potassium in the diet to help lower blood pressure. Salt substitutes that contain potassium thus address the problem in two different ways.

Potassium Chloride

Chemical Formula

KCI

Synonyms

Salt

Description

White crystals.

Uses

Potassium chloride is used as an essential nutrient and as a salt sub- stitute. 89

Why There's Antifreeze in Your Toothpaste

Potassium as a nutrient lowers blood pressure, prevents bone loss, and reduces the risk of kidney stones. Some of these effects are due to the loss of sodium in the urine when potassium is ingested. In salt substitutes, the metallic or bitter taste of potassium chlo- ride is often masked by other ingredients, such as the amino acid L- lysine, tricalcium phosphate, citric acid, and glutamic acid.

Fats

9 Fats are food. But apart from their nutritive value they are also used as ingredients to modify other foods. Flaky piecrusts, smooth ice cream, and melt-in-your-mouth chocolates owe their properties to the unique characteristics of fats and oils. Because fats are the most concentrated form of calories in foods, there are many reasons to try to attain those properties without all the calories. That's where vegetable gums and modified fats enter the pic- ture.

Tristearin

Chemical Formula

II

o o

Synonyms

Glycerol tristearate

Why There's Antifreeze in Your Toothpaste

Description

White greasy solid.

Uses

Tristearin is the primary fat in beef. It is a triglyceride, a molecule of glycerin that has reacted with three molecules of the fatty acid stearic acid. Tristearin is a saturated fat. This means that every carbon has as many hydrogen atoms as it can hold-it is saturated with hydrogen- and there are no double bonds between any two carbons. Carbon can form four bonds. If a carbon is attached to two other carbons in a chain, the atom has two bonds left that can attach to hydrogens. Single bonds are flexible, and can bend and rotate easily. Double bonds are more rigid. A rigid bond does not allow the molecules to fit together easily, so they can't pack tightly into a solid. Saturated fats are usually solid, while unsaturated fats or polyun- saturated fats (which have two or more double bonds) are usually liq- uid at room temperature.

Focus: Fats

Flaky piecrusts used to contain lard, or at least butter.

Solid fats are important in baking, as they separate

sheets of dough into thin, independent flakes.

Traditional solid fats are animal-derived saturated fats,

such as lard and butter. Some vegetable fats, such as coconut and palm kernel oils, are solid, but they are more expensive than some liquid vegetable oils like corn oil, cottonseed oil, or soy- bean oil. These oils come from plants that are used for more than just the oil they provide. Using several different parts of the plant makes growing them more economical. Saturated fats like the tristearin in beef fat have higher melt- ing points than the unsaturated fats in vegetable oils like trilin- olein or trilinolenin.

Fats

Shortening

Vegetable oils can be made into solids by converting some of the double bonds in their molecules into single bonds. This is done by adding hydrogen, and is called hydrogenation. A catalyst such as platinum is used to convert one or more double bonds to sin- gle bonds with an attached hydrogen. Some of the double bonds are converted from the normal cis orientation, with both hydro- gens on the same side of the bond, to the trans orientation, with a hydrogen on either side of the bond. Such fats are called trans fats, and are implicated in cardiovascular problems. With the double bonds converted to single bonds, the molecules can fold and twist more easily, and the fat is now a solid.

Shortening also contains pieces of fats called monoglyc-

erides and diglycerides. These are emulsifying agents that allow water and air to be whipped into the shortening and help to thicken it and make it gel.

Trilinolein

Chemical Formula

Synonyms

Glycerol trilinoleate

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Description

Yellowish clear oil.

Uses

Trilinolein is a polyunsaturated fat. This type of fat is an antioxidant that has been linked to a number of potential cardiovascular health benefits. It is found in seed oils such as safflower oil and linseed oil. The double bonds that make this an unsaturated fat prevent the molecule from bending; they lower the melting point making a liq- uid oil rather than a solid fat. Polyunsaturated fats can combine easily with oxygen at the points where there is a double bond between two carbon atoms. This is why they make good antioxidants; they combine with the oxygen free rad- icals so they don't damage other molecules. It is also how oils harden, and is thus important to painters. Oil paints made with linseed oil are almost three-quarters trilinolein. They dry to form a tough plastic film that incorporates the pigments and holds them onto the surface to be painted.

Trilinolenin

Chemical Formula

Synonyms

Glycerol trilinolenate

Description

Yellowish clear oil.

Fats

Uses

Trilinolenin is an omega-3 polyunsaturated fat. This type of fat, like trilineolin, has been linked to a number of beneficial health effects, and it is an antioxidant. It is found in oils such as soybean oil and lin- seed oil. Omega-3 refers to a situation in which the first (or only) double bond is located on the fatty acid. The last carbon is called the omega carbon (omega is the last letter in the Greek alphabet). If there is a double bond between the third and fourth carbons from the end, the omega-3 and omega-4 carbons, then the oil is an omega-3 fat. Omega-3 fats are known for their beneficial cardiovascular effects.

Fat Substitutes

Olestra

Chemical Formula

Synonyms

Sucrose octaester • sucrose polyester

Why There's Antifreeze in Your Toothpaste

Description

Amber medium-viscosity liquid.

Olestra is a nondigestible plastic, made by adding eight fatty acid molecules to the sugar molecule sucrose.

The fatty acids block access to the sugar, so enzymes can't break it down.

The result is a molecule that behaves like a fat, but cannot be digested by humans.

Because Olestra is not digested, it behaves much like mineral oil.

The laxative properties, which are widely discussed, appear on the label.

Like other indigestible lipids, Olestra can dissolve fat-soluble vitamins and carotenoids, which makes them unavailable for absorption.

Most users do not encounter problems.

It is unclear at this time whether affected individuals cease to be affected over time, as they do with sorbitol and some other sugar alcohols that produce similar problems.

Olestra's manufacturing process creates many different molecules, some with fewer than eight fatty acids, and with many different fatty acid chains other than those pictured above.

Uses

Currently, Olestra is only approved for use in savory snacks, such as potato chips. The molecules in Olestra have been modified since it was first marketed, to avoid some ofthe more unpopular side effects, but some remain. Adding carotenoids and fat-soluble vitamins to the product has also been done, but this does not eliminate all of the problems with nutrient absorption.

Salatrim

Chemical Formula

II

0/'...../ o

II

o o

II

O~

Fats

Synonyms

Structured triglyceride· Benefat

Description

Solid fat. Salatrim is a mixture of many triglycerides that have the charac- teristics mentioned above. Because it is partially absorbed, Salatrim does not have the problems associated with Olestra. It does not have any laxative effects nor does it prevent the absorption of fat-soluble vitamins and carotenoids. The available calories from Salatrim are only 55 percent of those from normal fats.

Uses

Salatrim is a fat (triglyceride), and can be used where fats are used in cooking. It is not as easily absorbed as other fats. This is because the main long-chain fatty acid in it is stearic acid, which by itself is less well absorbed than others, and because it is even less well absorbed when combined with short-chain organic acids like acetic (with two carbons), propionic (with three carbons), and butyric (with four car- bons) acids. Short-chain organic acids have less energy storage capac- ity than long-chain fatty acids. The very short chains are closer to carbohydrates (in calories) than they are to fats.

Guar Gum

Chemical Formula

OH

O~HOH

o 0

OH

O~H

OH

o OH

OH

Why There's Antifreeze in Your Toothpaste

Description

Yellowish powder. Guar gum is a polysaccharide (a long chain made of sugars) com- posed of the sugars galactose and mannose. Some other familiar poly- saccharides are starch and cellulose, which are made of long chains of the sugar glucose. Guar gum comes from the endosperm of the seed of the legume plant Cyamopsis tetragonoloba. Cyamopsis tetragonoloba is an annual plant, grown in arid regions of India as a food crop for animals.

Uses

Guar gum is used as a thickener in cosmetics, sauces, salad dressings; as an agent in ice cream to prevent ice crystals from forming; and as a fat substitute that adds the "mouth feel" of fat. In pastry fillings, it prevents syneresis (weeping of the water in the filling), keeping the pastry crust crisp. It has a high viscosity (thickness) even when very little is used. When mixed with xanthan gum or locust bean gum, the viscos- ity is more than when either one is used alone, so less of each can be used.

Focus: Ice Cream

15") f ~ Ice cream is more American than apple pie. Thomas Jef-

Il~

\ ferson made ice cream at Monticello. George Washing- \..

ton loved ice cream. It is said that ice cream is not

//! I

food, it is medicine, capable of curing melancholy and t.:." lifting spirits, drowning sorrows, and bringing smiles to the most defeated of little soccer players. Ice cream at its simplest is made of milk, sugar, cream, and some flavoring, such as fruit puree or vanilla. An essential ingre- dient in addition to those is air, without which ice cream would not be the special treat it is. In the United States, ice cream must contain at least 10 per- cent milk fat, and at most 50 percent air, and must weigh at least

Fats

99 4.5 pounds per gallon. Ice creams labeled "premium" and "super premium" have higher fat content (13 to 17 percent) and lower air content (known in the ice cream trade as "overrun").

Ice Cream Ingredients

The milk and cream in ice cream contain butterfat, proteins, and milk sugars. Butterfat adds rich flavor, smooth texture, body, and good melting properties. The triglycerides in butterfat melt over a wide range of temperatures, so there is always some bit of solid and some liquid butterfat. Some of the butterfat almost turns into butter while the ice cream is being churned, adding to the unique texture of ice cream. The proteins in ice cream help to incorporate air into the mixture; the air forms small bubbles. The proteins modify the texture of the ice cream in other ways as well, making it chewier and giving it body. The proteins also help to emulsify the fats, keeping the fat globules suspended in the mix. The proteins coat each fat globule and keep them from sticking together.

However, making the globules stick together in chains and

meshlike structures is important to ensuring the ice cream's tex- ture, its ability to hold air, and its ability to stay firm as the ice inside melts. Emulsifiers, such as the lecithin in egg yolks, stick their fatty-acid ends into the fat globules and prevent the pro- teins from completely coating the fat. This balance between pro- teins and emulsifiers allows the fat globules to chain and stack without flowing together. The milk sugar lowers the freezing point of the water in ice cream. Adding extra sweeteners, such as sugar and corn syrup, also has this effect. This ensures that a portion of the water never freezes, keeping the ice cream from becoming a solid chunk of ice. Added sweeteners are inexpensive, and they make up about 15 percent of the mix by weight. The use of high-fruc- tose corn syrup will reduce the freezing point further than sugar, resulting in a softer ice cream.

Why There's Antifreeze in Your Toothpaste

Ice Cream Additives

As ice creams move down the scale from premium, getting lower in fat and incorporating more air, ingredients are added to make up for the loss of creamy texture-and to help keep all of the extra air whipped up.

Emulsifiers such as the monoglyceride glycerol monostearate

and related diglycerides help to keep the milk fat in suspension, and limit the growth of ice crystals. Other emulsifiers such as lecithin and polysorbate 80 perform similar functions. Emulsifiers have a significant effect on making the fat globules stick together in chains, rather than flowing together in larger globules, or stay- ing separated as tiny ones. This adds to the structure of the ice cream, as it affects the texture and the ability to incorporate air into the mixture.

Gums such as guar gum, locust bean gum, xanthan gum,

carrageenan, and methylcellulose help to prevent ice crystals from forming during freezing and refreezing after a trip from the grocery store. They also have a "mouth feel" similar to milk fat, so the milk fat is not missed as much as it might be in low-fat ice creams. Like emulsifiers, gums also aid in keeping the air whipped into the mix. Gums keep the ice cream from becoming grainy due to crystals forming from either ice or lactose.

Some ice creams contain sodium citrate to decrease the ten-

dency of fat globules to coalesce, and to decrease protein aggre- gation. This results in a wetter ice cream. The citrates and phosphates are both used for this effect. Calcium and magne- sium salts have the opposite effect, making a dryer ice cream.

Other Icy Treats

Sherbet

Sherbets have a milk-fat content between 1 and 2 percent, and they usually contain more sugar. Often flavored with fruit, a gal- Ion of sherbet weighs a minimum of six pounds.

Fats

Sorbet

Water ices and sorbets are similar to sherbet, but contain no dairy products.

Gelato

Gelato is made of sugar, milk, cream, egg yolks, and flavorings, and is usually served semifrozen. locust Bean Gum

Chemical Formula

OH

Synonyms

Carob bean gum

OHO

OH

OHOH

OH

Description

Off-white powder. Locust bean gum is a polysaccharide (a long chain made of sug- ars) made of the sugars galactose and mannose. Some other familiar

Why There's Antifreeze in Your Toothpaste

polysaccharides are starch and cellulose, which are made of long chains of the sugar glucose. In locust bean gum, the ratio of mannose to galactose is higher than in guar gum, giving it slightly different properties, and allowing the two gums to interact synergistically so that together they are able to make a thicker gel than either one would do alone. Locust bean gum is extracted from the endosperm of the seeds of the carob tree, Ceratonia siliqua, which grows in Mediterranean countries.

Uses

The ancient Egyptians used locust bean gum to bind the wrapping of mummies. In more recent times it is used as a thickener in salad dressings, cosmetics, and sauces; as an agent in ice cream that prevents ice crys- tals from forming; and as a fat substitute. In pastry fillings, it prevents syneresis (weeping of the water in the filling), keeping the pastry crust cnsp. It has a very high viscosity (thickness) even when very little is used.

Xanthan Gum

Chemical Formula

Xanthan gum is a long-chain polysaccharide composed of the sug- ars glucose, mannose, and glucuronic acid. The backbone is sim- ilar to cellulose, with added side chains of trisaccharides (three sugars in a chain).

Description

Creamy white crystalline powder. A polysaccharide such as xanthan gum is a chain of sugars. Some familiar polysaccharides are starch and cellulose. The backbone of xanthan gum is similar to cellulose, but the trisaccharide side chains of mannose and glucuronic acid make the molecule rigid, and allow it to form a right-handed helix. These features make it interact with

Fats

103 itself and with other long-chain molecules to form thick mixtures and gels in water. Xanthan gum is a slimy gel produced by the bacterium Xan- thomonas campestris, which causes black rot on cruciferous vegeta- bles, such as cauliflower and broccoli. The slime protects the bacterium from viruses and prevents it from drying out.

Uses

Xanthan gum is used as a thickener in sauces, as an agent in ice cream that prevents ice crystals from forming, and as a fat substitute that adds the "mouth feel" of fat without the calories. It is used in canned pet food to add "cling." In pastry fillings, it prevents syneresis (weep- ing of the water in the filling), protecting the crispness of the crust. It has a very high viscosity (thickness) even when very little is used. When mixed with guar gum or locust bean gum, the viscosity is more than when either one is used alone, so less of each can be used.

Colors

10 Many foods and products become much more appealing if they have color. Margarine would look like vegetable shortening if it weren't for added color. Some colors are nutrients in their own right, and they have antioxidant properties that are beneficial to health. Beta-carotene, annatto, saffron, and turmeric all have these good properties in addi- tion to their color. In fact, the same chemistry that makes them absorb light also helps them to absorb and neutralize dangerous oxygen free radicals in the body.

Annatto

Chemical Formula

0,,

OH

o -"';:::0 ./

Bixin

Why There's Antifreeze in Your Toothpaste

o ~

OH

Norbixin

Synonyms

Bixin carotenoids

Description

Annatto is a colored pigment that is extracted from the Central and South American plant Bixa orellana. The color comes from the resinous outer covering of the seeds of the plant, which is composed of the carotenoid pigments bixin and norbixin and their esters. The central portion of those molecules is the same as that of the molecule beta-carotene, and the yellow-orange color of annatto comes from the same physical chemistry origins as the orange color of beta-carotene.

Uses

Annatto provides color in cheese, butter, margarine, and microwave popcorn. It is often used as a substitute for the expensive herb saffron. It also has antioxidant properties. The seeds are used as a flavoring in the form of a powder or a paste, but the main use is as a coloring agent. Because annatto binds well to the proteins in dairy foods, it is often used to add color to milk products such as butter, cheese, or puddings.

Colors

Beta-carotene

Chemical Formula

Synonyms

l3-carotene

Description

Yellow powder. Beta-carotene is one of the orange dyes found in most green leaves and in carrots. When leaves lose their chlorophyll in the fall, carotene is one of the colors left over in the leaf.

Uses

Beta-carotene is used in foods to provide color (margarine would look as white as vegetable shortening without it). Another similar mole- cule, annatto, is used in cheeses. Another famous carotenoid dye, saf- fron, is used to color rice and other foods. Beta-carotene is sometimes added to products for its antioxidant effects, to keep fats from going rancid. The same long chains of con- jugated double bonds (alternating single and double bonds) that give the carotenes their colors are also the reason they make good antiox- idants. They can mop up oxygen free radicals and dissipate their energy. The body turns beta-carotene into vitamin A, and it is sometimes added to foods or vitamin supplements as a nutrient.

Why There's Antifreeze in Your Toothpaste

~ Chemistry Lesson

Lycopene

Another colorful carotene is lycopene.

This is the red molecule that gives ripe tomatoes their color.

Notice the alternating double and single bonds between the car- bon atoms.

These are called conjugated bonds, or resonance bonds.

The electrons in those bonds are not locked on to one atom-instead they spend their time bouncing from atom to atom.

This gives the effect ofsomething in between a double bond and a single bond, more of a one-and-a-half bond.

The long chain of conjugated bonds acts like a wire, allowing the electrical energy to move from one side of the molecule to the other.

The energy can slosh around like water in a bathtub.

Normally it takes quite a bit of energy to move an electron away from an atom.

X-rays or high-energy ultraviolet light can move an electron into a higher orbit in an atom, but ordinary visible light does not have enough energy.

A molecule of lycopene can absorb blue light because the elec- trons are not orbiting a single atom, they are sloshing around orbit- ing many atoms, and the energy needed to move them is a lot less than in a smaller molecule, or one without conjugated bonds.

You can think of the energy in a lycopene molecule as a wave sloshing in a bathtub, or the wave you can make with a jump rope.

The lowest energy state, called the ground state, would correspond to the jump rope going around in the normal fashion.

Colors

109 Each end of the jump rope is a node, a place where the rope doesn't move. It is possible to get a jump rope to have three nodes, as you may have done as a child. It acts like there are two jump ropes, each one half the length of the other. The energy sloshing around in the lycopene molecule can do the same thing. Absorbing a photon of green light makes it act as if the molecule were two molecules, each half as long. The molecule has absorbed the green light. White light that is missing its green light looks red. Beta-carotene absorbs blue light, so it looks orange.

Anthocyanins

Another class of colored compounds is the anthocyanins. Flowers, blueberries, apples, and red cabbage get their color from antho- cyanins, which are part of a group of compounds known as flavenoids.

Anthocyanins can change their color, depending on how acidic

or alkaline they are.

Why There's Antifreeze in Your Toothpaste

OH

HO

o :/'

O-Sugar

OH

Cyanidin 3-glucoside

In neutral conditions, the molecule has no charge. It absorbs yel- low light and appears purple. Notice all the alternating single and double bonds.

OH

HO

OH

In an acid (pH less than 3), the acid donates a hydrogen nucleus, and the molecule becomes positive. The bond next to the oxygen becomes a double bond, and the molecule now absorbs green light, so it appears red.

HO

O-Sugar

OH

Colors

111 In an alkaline solution, the molecule donates a hydrogen nucleus, and a hydroxyl group becomes an oxygen atom with a negative charge. The molecule now absorbs orange light and appears blue. You can try this yourself at home. You need some purple grape juice, blueberry juice, or the water left over after boiling a red cabbage. If you add clear distilled vinegar, the juice will turn red. If you add baking soda, the juice will turn blue. You can learn more about molecules that absorb different colors in the section on para-amino benzoic acid (PABA).

Carmine

Chemical Formula

Synonyms

Cochineal extract· 7-D-glucopyranosyl-3,5,6,8-tetrahydroxy-l-methyl- 9.1O-dioxoanthracene-2-carboxylic acid

Description

Carmine is a colored pigment extracted from the female insect Coc- cus cacti or Dactylopius coccus, or its eggs. These insects live on prickly pear cactus in Mexico. The Spanish conquistador Hernan Cortes brought the dye to Europe after seeing the Aztecs use it. It takes more than a million of the insects to make a pound of dye. The insects are harvested when the females are about to lay eggs, at which time they turn a bright red color. First, the shells of the female insects are dried; next, the color is dissolved in a solvent and all of the

Why There's Antifreeze in Your Toothpaste

excess insect parts are filtered out. Because of this labor-intensive pro- cessing, carmine is more expensive than FD&C Red #40. It has a deep magenta color, while Red #40 is more of an orange-red.

Because carmine comes from insects, some other color must be

used if a product is to be labeled kosher.

Uses

Carmine (or cochineal) is used as a colorant in food, cosmetics, and paints. Carminic acid is orange in acidic media (pH 3), red in nearly neu- tral media (pH 5.5), and purple at pH 7. It forms complexes with met- als such as tin and aluminum to make brilliant red pigments. Carmine is easily bleached by sulfur dioxide. Carminic acid is related to another dye molecule, alizarin.

Alizarin 6

Also note the similarity to erythrosin B, known as FD&C Red #3

Erythrosin B

Colors

Focus: Food, Drug, and Cosmetic Colors

The term "FD&C color," often seen on ingredients

~ labels, refers to food, drug, and cosmetic colors. c., •

These are organic compounds (as opposed to

inorganic pigments, such as titanium dioxide) that are so intense in color that it takes only very tiny amounts to color something, and thus they can be used in concentrations so minute that they are safe for consumption.

As further described in the section on beta-carotene, organic

dyes owe their colors to resonance structures in the molecule, where charges are free to move in the molecule at frequencies that fall in the range of visible light. There are only seven non-natural (artificial) colors certified

for consumption in the United States

• FD&C Blue #1: Erioglaucine • FD&C Blue #2: Indigotine • FD&C Green #3: Fast Green • FD&C Red #3: Erythrosin B • FD&C Red #40: Allura Red • FD&C Yellow #5: Tartrazine • FD&C Yellow #6: Sunset Yellow The dye Orange B is allowed only in hot dog and sausage casings. Other FD&C colors are used in drug coatings and cosmetics. If one of the above colors is used in a food product, it must be explicitly mentioned in the ingredients list. If the label does not name the compound specifically, but simply says something like "contains artificial color," then you know it does not contain one of the colors listed above. A pigment is a solid that has a color. A dye is a liquid that has a color. FD&C colors are all dyes. To make a solid color from a dye, the dye is used to color a solid substance. The result is

Why There's Antifreeze in Your Toothpaste

called a lake. One common substrate used is aluminum hydrox- ide, commonly used as an antacid. A color made this way might be labeled "Red 40 Aluminum Lake." Lakes are often used on the outside of candies and pills, so that the dye does not wash off or rub off.

Natural Colors

Besides artificial colors, many natural colors are used in foods.

Some of these are

• annatto • beta-carotene • carmine • saffron • turmeric • indigo

Pigments such as titanium dioxide and ferrous gluconate are

also added to foods.

Caramel Color

One of the most widely used colors is caramel, which is the color of burnt sugar. There are many different types of caramel color, each engineered to serve a particular purpose in food chemistry. They are all based on the cooking of sugars and starches. Sometimes acids such as acetic acid, citric acid, lactic acid, or phosphoric acid are used to break the bonds between sugars to create invert sugars, or to make sugars from starches, before the sugars are raised to a higher temperature for caramelization.

The heat is carefully controlled during caramelization to get

the right products from the reaction. Besides acids, alkalies and salts may be used to further control the process.

Colors

115 Caramel color is a colloid, a mixture in which solid particles are suspended in water. The particles in colloids have electric charges that keep the particles from clumping together and set- tling out of solution. The charges can be positive or negative. If a negative colloid is added to a product that has positive colloidal particles in it, the two will attract one another and clump up, making the product cloudy.

Caramel color can be made with either positively or nega-

tively charged particles. This allows manufacturers to use nega- tive colloidal caramel in acidic soft drinks, and positive colloidal caramel in beers and soy sauces. Beer has positively charged proteins suspended in it, and soy sauce has a high salt content that requires the more salt-tolerant positive caramel color. Caramel color is an emulsifying agent as well as a colorant. In soft drinks, it helps keep the flavor oils suspended in the solution. In chocolate milk, the muddy color of caramel is darkened by the addition of FD&C Red #40 to give what the industry refers to as a Dutch chocolate shade. Blues and yellows are sometimes added to create a browner color. Caramel color is added to baked goods, poultry, and milk (to give it an "eggnog" color), and to malt vinegars, canned meats, syrups, and soups, stews, and gravies.

Why There's Antifreeze in Your Toothpaste

Saffron

Chemical Formula

OH

o o

OH

HO

OH

HO

Colors

Synonyms

Beta-gentiobiose crocetin • saffron carotenoids

Description

Saffron is the tiny stigma at the center of the crocus flower, Crocus sativus. Because each stigma is plucked from the flower by hand, saf- fron is one of the most expensive spices in use today. The dye molecule in saffron is the carotenoid beta-gentiobiose crocetin. It is related to beta-carotene, and you can see the relation- ship in the center of the molecule. That center portion is the

carotenoid pigment crocetin

O~

OH

Crocetin

HO

~o On either side of the crocetin molecule is a disaccharide molecule called beta-gentiobiose, and the result is the molecule that gives saf- fron its yellow color.

Uses

Saffron is a spice that is used sometimes for flavor, but mostly for the yellow color it imparts to foods. Because of its expense, saffron is often replaced in recipes by another carotenoid, annatto, or the unrelated dye molecule in turmeric. Like the other carotenoid dyes, saffron is an antioxidant, but its expense makes it unsuitable as a preservative or dietary supplement.

Why There's Antifreeze in Your Toothpaste

Turmeric

Chemical Formula

HO

Synonyms

Curcumin

Description

Curcumin is the main color found in the root of the turmeric plant Curcuma Zanga, grown in south Asia.

Uses

Ground turmeric rhizome is one of the main ingredients in curry powder. Its bright yellow color makes it a natural substitute for the much more expensive herb saffron. Because turmeric fades with exposure to light, other colors are necessary if a product is to be displayed in a clear container.

Titanium Dioxide

See entry, page 12.

Allura Red

IIs- 0-

Na+

IIo

OH

-0

N=N

Chemical Formula

Na+

-0 ............ ~O

~S:/"

O~

-;//

Colors

Synonyms

FD&C Red #40 • 6-hydroxy-5-(2-methoxy-5-methyl-4-sulfophenyl-

azo)-2-naphtalenesulfonic acid sodium salt

Description

Red dye.

Uses

FD&C Red #40 is used as a coloring agent in a wide array of products, such as orange soda. It is related to several other dyes, including FD&C

Yellow #6

Na+

OH

-o- ~

N=N

~ /; n- 0-

Na+

the food color Scarlet GN (FD&C Red #4)

0=8=0

N=N):>-

0=8=0

OH

Na+

-0-1 #LN=N

!/\d- o

the food color tartrazine (FD&C Yellow #5)

O~

/0- '-'::8/

OH M

""0

/ -N

Na+

OH

Why There's Antifreeze in Your Toothpaste

and the closely related dye Orange B

Na+

0:::::-... /0- Na+ ~S/ ~ ~O Yellow #5 and #6 are widely used in candies and drug coatings. Orange B is used in hot dog and sausage casings. Some people are sen- sitive to Yellow #5; reactions to it can be severe enough that specific labeling is required for prescription medicines that contain it. None of the other certified dyes have this special requirement. ~ Chemistry Lesson The dyes on the group above are known as azo dyes, because they have the two nitrogen atoms together in the center (called an azo group). These dyes were originally derived from coal tar, but are now mostly made from petroleum. Azo dyes come in many colors besides those allowed in food (listed above). The other colors find use in fabrics, paper products, and plastics.

Colors

Indigo

Chemical Formula

Synonyms

Indigotine • FD&C Blue #2

Description

Blue dye. Indigo was originally made from two plants. One is woad, Isatis tinctoria, a native of Greece and Italy, and the other is indigo, Indigofera tinctoria, a native of India. At the end of the nineteenth cen- tury, German scientists synthesized the dye, and production from plant sources declined. Most of the dye today comes from China. Recently, bacteria have been genetically engineered to produce indigo dye.

Uses

Indigo is the dye used to color blue jeans. It is also used in foods under the name FD&C Blue #2. Other closely related dyes are erioglaucine,

known as FD&C Blue #1

Why There's Antifreeze in Your Toothpaste

and Fast Green, FD&C Green #3

HO

Caseinates

Chemical Formula

Casein proteins are composed of the following amino acids

• 20.2 percent glutamic acid • 10.2 percent proline • 8.3 percent leucine* • 7.4 percent Iysine*

Colors

123 • 6.5 percent valine* • 6.4 percent aspartic acid • 5.7 percent serine • 5.7 percent tyrosine • 5.5 percent isoleucine* • 4.5 percent phenylalanine* • 4.4 percent threonine* • 3.7 percent arginine • 2.8 percent histidine • 2.7 percent alanine • 2.5 percent methionine* • 2.4 percent glycine • 1.1 percent tryptophan* • 0.3 percent cystine

The amino acids marked with an asterisk are called essential

amino acids, because they cannot be synthesized in the human body and must be obtained directly from food. All eight essential amino acids are present in casein protein.

Synonyms

Milk solids

Description

White powder. Calcium caseinate is produced from skim milk by adding an acid to cause the protein to coagulate, at which point it can be filtered to sep- arate the curds from the whey.

Sodium caseinate is produced by reacting the acid casein with

sodium hydroxide.

Uses

Caseins are used in wine making to clarify the wine by causing fine particles to coagulate with the protein so they can be easily filtered out or precipitated. In addition to their nutrient value, casein proteins have many other ~ses. They are good emulsifiers, helping fats to stay suspended in water- based products such as milkshakes, coffee creamers, and ice creams. They are used as binders in processed meats (lunch meats, sausages, etc.).

Why There's Antifreeze in Your Toothpaste

Caseinates are used as sources of nutritional protein. Casein proteins were one of the first plastics, and they are still in use for this purpose. Thin plastic films of casein can be made by adding glycerol or sorbitol as a plasticizer, a substance that lowers the temperature at which a plastic softens, and makes it more pliable. Caseins are used as food colorants because they make a nice base of opaque white, which can then be tinted with other colors as required.

Ferrous Gluconate

Chemical Formula

OH

HO

HO HO

HO~O

O~OH

OH

0- +Fe+ -0

HO

Synonyms

Iron (II) di-D-gluconate

Description

Ferrous gluconate is a black dye. It is composed of iron bound to two molecules of gluconic acid, which is the acid form of glucose.

Uses

Ferrous gluconate is the black dye used to color ripe olives. It is also used as an iron supplement to treat iron-deficiency anemia.

Moisture Controllers 11

Moisture controllers attract water. Sometimes they work so well that they actually pull water from the air. The liquid center of chocolate- covered cherries can be created by adding glycerin to the fondant that is molded around the cherry before it is dipped in chocolate. Over time, the glycerin absorbs so much water from the cherry that the fon- dant dissolves, making a liquid syrup inside the chocolate shell.

Glycerin

See entry, page 58.

Sorbitol

See entry, page 83. 125

Why There's Antifreeze in Your Toothpaste

Sodium peA

Chemical Formula

O~ONa

Synonyms

Sodium-2-pyrrolidone carboxylate

Description

Pale yellow clear liquid.

Uses

Sodium PCA is hygroscopic, attracting moisture from the air. It is used as a humectant (moisturizer) for hair- and skin-care products. It is a stronger hydrating agent than the traditional compounds used for this purpose, such as glycerin, propylene glycol, or sorbitol.

Mannitol

See entry, page 84.

Propylene Glycol

See Glycols entry, page 42.

Butylene Glycol

See Glycols entry, page 42.

Panthenol

Chemical Formula

. Y 1

HO~ Y

-NH~OH

OH

Moisture Controllers

Synonyms

Vitamin B5

Description

Off-white crystalline powder. Panthenol is the alcohol form of pantothenic acid, more familiar as vitamin B5. In a living cell, panthenol is converted to pantothenic acid, which then becomes an important part of the compound coen- zyme A, which is important in cellular metabolism. In hair, which contains no living cells, it remains panthenol. Because it could become a vitamin if it were ever to get to a liv- ing cell, it is marketed as a "provitamin," even though its effects as a vitamin are never realized.

Uses

Because panthenol binds well to hair follicles and attracts moisture from the air, it is a moisturizing agent used in shampoos and condi- tioners. It lubricates the hair without feeling greasy. Instead, it smoothes roughened hair surfaces, making them shiny and easier to comb. Contrary to advertising, panthenol does not nourish hair; instead it coats the hair and makes it slippery.

Emulsifiers

12 Emulsifiers are similar to detergents in that one end attracts water while the other attracts fats and oils. They are used to mix oil and water to make products such as mayonnaise, sauces, paints, and med- icines. lecithin See entry, page 20.

Phosphoric Acid

See entry, page 47.

Sorbitan Monostearate

Chemical Formula

o ~oll

OH

Why There's Antifreeze in Your Toothpaste

Synonyms

SPAN 60 • synthetic wax

Description

Waxlike creamy white powder. Sorbitan monostearate is an ester of sorbitol and stearic acid. The sorbitol end of the molecule is highly soluble in water. The stearic acid end is soluble in fats. These properties allow the molecule to excel at making emulsions of oil and water.

Uses

Sorbitan monostearate is used as an emulsifying agent in cake mixes, icings, baked goods, puddings, imitation whipped cream, hemor- rhoid creams, and creams to treat dry skin. It is often used with polysorbate 80. Similar molecules can be made using other fatty acids, such as the shorter-chained lauric acid. a

OH

Sorbitan monolaurate

~ Chemistry Lesson An emulsion is a mixture of oil and water. Some emulsions, such as butter and margarine, have tiny droplets of water in the oil. Others, like cream or mayonnaise, are droplets of oil in water. The choice of emulsifier has a large part to play in which kind of emulsion you get. Emulsifiers that are soluble in water generally have shorter chains of fats. These make emulsions of oil in water. Emulsi-

Emulsifiers

131 fiers that have long-chain fats, or several chains, are more soluble in oil than they are in water. These make emulsions of water in oil. The emulsifier polysorbate 80 is at the water-soluble end of the spectrum, making good emulsions of oil in water. The emulsifier glycerol monostearate is closer to the oil-soluble end of the spectrum, making good emulsions of water in oil.

Somewhere in the middle are soy lecithin and sorbitan mono-

laurate, which make good foam stabilizers in whipped cream and sim- ilar products.

Polysorbate 80

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

Polyoxyethylene sorbitan monooleate • (x)-sorbitan mono-9-octade- cenoate poly(oxy-l ,2-ethanediyl)

Description

Amber-colored viscous liquid.

Uses

Polysorbate 80 is an emulsifying agent that is often used in ice cream to prevent milk proteins from completely coating the fat droplets. This allows them to join together in chains and nets, to hold air in the mix- ture, and to provide a firmer texture that holds its shape as the ice cream melts. Similar compounds are polysorbate 60, polysorbate 65, etc.

Glycerol Monostearate

Chemical Formula

CH3(CH2)16COOCH2CHOHCHPH

OH

Synonyms

Glyceryl stearate· mono- and diglycerides • monostearin • octade- canoic acid monoester with 1,2,3-propanetriol

Description

White or cream-colored waxy solid.

Emulsifiers

Uses

Monoglycerides are used as emulsifying agents in many products, such as baked goods, whipped cream, and ice cream. A monoglyceride is a fat that is missing two of its fatty acids. It is often used with diglycerides, which are fats that are only missing one of their fatty acids.

Tetrasodium Pyrophosphate

See entry, page 46.

Focus: Whipped Cream

(li The inventor of butter must have been an interesting person. What kind of person would shake a bunch of cream until his or her arms could shake no more, just to see what would happen? And who would keep going after the cream had whipped into the delight put on top of pies and sundaes for dessert?

Whipping cream is cream that contains at least 30 percent

milk fat. Cream that has less than 30 percent fat will not whip. Heavy cream can contain up to 40 percent milk fat, and is some- times used for whipping. The structure of whipped cream is quite complex. A coating of milk protein surrounds small globules of milk fat containing both solid and liquid fats. These globules stack into chains and nets around air bubbles. The air bubbles are also formed from the milk proteins, which create a thin membrane around the air pockets. The three-dimensional network of joined fat globules and protein films stabilizes the foam, keeping the whipped cream stiff.

Whipped Cream Additives

Additives are sometimes added to whipping cream to make it

easier to incorporate more air, or to make it more stable, so the

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foam lasts longer. Chief among the stabilizers are carrageenan and emulsifiers such as glycerol monostearate (a monoglyceride) and related compounds called diglycerides. Carrageenan is a gelling agent that forms a complex with the milk proteins, adding bulk and strength. A small amount will make a large difference in the ability to hold air in the foam.

Mono- and diglycerides replace some of the proteins in the

coating around the fat globules. This lets the globules partially fuse together to form the chains and networks that make up the three-dimensional structure of the foam. There are naturally occurring mono- and diglycerides in milk and cream, but adding more makes the whipped cream last longer and helps achieve higher volume.

Sweeteners such as sugar and corn syrup are added for

taste, but they also participate in the structure of the foam and in the weight of the final product.

Natural and artificial flavors are also added, usually in the

form of vanilla extract or synthetic vanillin or ethyl vanillin.

Propellant in Canned Whipping Cream

In canned whipping cream, the gas nitrous oxide is used as both a propellant and a whipping agent. Nitrous oxide under pressure dissolves in the fats in the cream, and comes out of solution (like fizzing carbon dioxide in a soda) when the pressure is released. The bubbles of nitrous oxide instantly whip the cream into foam.

Stabilizers and

Thickeners

13 Stabilizers work with emulsifiers to prevent the fats and oils from sep- arating. They can be emulsifiers themselves, or they can be large mol- ecules, such as vegetable gums, that lock up the water in gels.

Corn Syrup

See Sugars entry, page 29.

Sodium Caseinate

See Caseinates entry, page 122.

Calcium Caseinate

See Caseinates entry, page 122. 135

Why There's Antifreeze in Your Toothpaste

Polyethylene Glycol

Chemical Formula

Synonyms

PEG- n: PEG-6, PEG-8, PEG-I2, PEG-40, PEG-ISO, etc.

Description

Polyethylene glycol is a family of long-chain polymers attached to a glycerin backbone.

Uses

PEG is used as a thickener in many products. It is used in toothpaste to prevent bacteria from breaking down the pyrophosphates that con- trol tartar buildup. PEGs are often reacted with fatty acids to make detergents that have thickening and foam-stabilizing properties. When chemically combined with fatty acids from coconut oil, they make detergents such as PEG-S cocamide, which is used in shampoos as a surfactant, emulsifier, and foam stabilizer.

Polypropylene Glycol

Chemical Formula

H" ~o~ ~o~ ~OyO"",

0 1 0

Synonyms

PPG-n: PPG-6, PPG-8, PPG-I2, PPG-40, PPG-ISO, etc.· PPG-I66/66 copolymer

Description

Polypropylene glycol is a family of long-chain polymers attached to a glycerin backbone.

Stabilizers and Thickeners

Uses

Like the closely related compound polyethylene glycol, PPG is used as a thickener in many products. It is used in toothpaste to prevent bac- teria from breaking down the pyrophosphates that control tartar buildup. lecithin See entry, page 20.

Methylcellulose

Sodium Carboxymethylcellulose

Chemical Formula

0- -0

OH

o 0- 0-

OH

Methylcellulose

II

/\ o

ONa

.. ·0

OH

o o

ONa

"'-I

IIo

OH

Sodium carboxymelhylcellulose

Why There's Antifreeze in Your Toothpaste

Synonyms

Hydroxymethylcellulose· carboxymethylcellulose

Description

Methylcellulose and carboxymethylcellulose are forms of the familiar polysaccharide cellulose that have been treated to make them more soluble in water. Cellulose is a long chain made of the sugar glucose. The long chains mix with water to create a thick syrup or gel.

Uses

Methylcellulose is used as a thickener in sauces and salad dressings, and as a thickener and stabilizer in ice cream, where it helps prevent ice crystals from forming during freezing or during refreezing after a thaw.

Xylenesulfonates

Chemical Formula

Synonyms

Ammonium xylenesulfonate • sodium xylenesulfonate • sodium

dimethylbenzenesulfonate

Description

Sodium xylenesulfonate (or its ammonium cousin) are hydrotropes- organic compounds that increase the ability of water to dissolve other molecules.

Stabilizers and Thickeners

Uses

Xylenesulfonates are used in detergents and shampoos in amounts of up to 10 percent of the product. They are surfactants, but they are usually added to thicken mix- tures such as shampoo, and to help keep some other ingredients in solution. This makes the product transparent, as the cloudy precipi- tates are put back into solution.

Agar

Chemical Formula

Synonyms

Seaweed extract

Description

Agar is made up of two polysaccharides, agaropectin and agarose. As with carrageenan, the backbone of these polysaccharides is the sugar galactose.

Uses

Agar is most familiar as the gelatinous growth medium used in petri dishes to culture bacteria. But it is also used in cooking as a gel for jel- lies and fillings. It is a soluble fiber, and as such it is quite useful as a laxative and diet aid. As a growth medium, agar has nice properties, such as a high melting point (85°C), and a lower solidifying point (40°C). It can stay

Why There's Antifreeze in Your Toothpaste

gelled at incubating temperatures. Purified agarose is used as a medium for electrophoresis, the separation of proteins or DNA frag- ments by size using an electric field.

Gelatin

Chemical Formula

Synonyms

Bone and skin extract· collagen

Description

White powder. Gelatin is a protein, made from the hydrolysis of collagen, a pro- tein that makes up about a third of all mammalian tissue. Collagen is a key component of connective tissues, tendons, and bones. Hydrolysis in proteins is the process of adding a molecule ofwater to break the bonds between some of the amino acids, thereby mak- ing the protein chains smaller. Collagen forms a triple helix, where three chains of connected amino acids form weak hydrogen bonds between the double-bonded oxygen atoms and the hydrogen atoms attached to the adjacent chain's nitrogens. The three chains then twist together like three cords in a rope. In gelatin, when the triple helixes are heated in water, they open up. Some of the hydrolyzed ends fray out to tangle with other ropes,

Stabilizers and Thickeners

141 and water is trapped in the strands. The result is a gel, a wiggly semi- solid mass.

Uses

Gelatin is very familiar as the gelling agent in Jell-O desserts. It is also used to thicken yogurt, sour cream, and ice creams. In its dried form it is used to make the dissolvable capsules that make medicines easier to swallow. In its unrefined form, gelatin is the hide glue used to hold violins together. Gelatin is the binder that makes marshmallows possible. It's also the ingredient that gives gummi bears their gumminess.

Pectin

Chemical Formula

Synonyms

Heterosaccharide gel • homogalacturonan

Why There's Antifreeze in Your Toothpaste

Description

Viscous, slightly milky liquid. Pectin is a long chain of pectic acid and pectinic acid molecules. Because these acids are sugars, pectin is categorized as a polysaccha- ride. It is prepared from citrus peels and the remains of apples after they are squeezed for juice. In the plant, pectin is the material that joins the plant cells together. When fungus enzymes break down the pectin in fruit, the fruit gets soft and mushy.

Uses

Pectin is a thickener in many products. If there is sufficient sugar in the mixture, pectin forms a firm gel. Jams and jellies are thickened with pectin. Pectin binds water, and thus keeps products from drying out. It stabilizes emulsions. Pectin combines with the calcium and whey proteins of milk, sta- bilizing foams and gels made with cream or milk. Pectin is not digested, and it is considered a beneficial dietary fiber.

Aiginafes

Chemical Formula

HO

Guluronic acid

OH

Mannuronic acid

Stabilizers and Thickeners

Synonyms

Kelp extract· furcellaran

Description

White powder.

Alginates are made up of long chains of two monomers

guluronic acid and mannuronic acid. The chains can be made of all one monomer or mixtures of both. The stems of kelp are made of chains with more guluronic acid, and the leaves (fronds) have more mannuronic acid. Guluronic chains bind tightly to calcium; in man- nuronic chains the calcium is more easily replaced by sodium, allow- ing the fibers to swell easily.

Uses

As with carrageenan, another seaweed extract, the ability to bind to calcium makes alginates useful in dairy products as a thickener. It also makes alginates useful as wound dressings, where they absorb fluids, and stop bleeding, and act as a scaffold. Alginates are used as thickeners in fat substitutes, pet food, stuffed olives, onion rings, low-fat sauces and spreads, and pie fillings. Propylene glycol alginate is stable in acids. It is used to preserve the foamy head on beers.

Starch and Modified Starch

Chemical Formula

OH

0/ ...

OH

Amylose

Why There's Antifreeze in Your Toothpaste

Amylopectin

Synonyms

Corn starch· polysaccharide· complex carbohydrate

Description

White powder. Starch is a polysaccharide, a chain of many glucose molecules. It is the main carbohydrate store in roots and seeds. There are two types of glucose chains in starch. One is a simple chain called amylose, and the other is a complex branched form called amylopectin. In the starch grains in a plant, amylopectin makes up the bulk of the material, from 50 to 80 percent by weight, made up of several million amylopectin molecules per starch grain. The rest is a much larger number of the smaller amylose chains, made up of 500 to 20,000 glucose units in each chain. Amylopectin molecules are made of several million glucose units.

Amylopectin

Stabilizers and Thickeners

Amylopectin forms branched structures with about 30 glucose

units in a chain between branches. This makes the molecule some- what striped in appearance, with the knotted branch points all in a row, and the smooth chains separating them. These molecules are so large that this striped appearance shows up under a light microscope, forming what appear to be growth rings in the starch grain.

Uses

Starch is a major source of calories in grains and tubers and foods made from them.

When starch is added to products as an ingredient, however, it is the functional properties of the starch that are usually important, not the calories.

Starch is the main thickener in gravies, sauces, and puddings.

It absorbs water, and becomes a gel when cooked.

As the starch swells up with water, the amylose leaches out, and the amylopectin forms the gel.

Some starches have higher amylopectin content and make bet- ter gels than those containing large amounts of amylose.

As a thickener (as opposed to a gel), it is amylose that has the main function.

The long water-soluble chains increase the viscosity, which doesn't change much with temperature.

Amylose chains tend to curl up into helixes (spirals) with the hydrophobic parts inside.

This allows them to trap oils, fats, and aroma molecules inside the helix.

Because starches are so good at absorbing water and bulking up, they are important in the texture of many food products.

They are often used as fat substitutes.

Not all of the starch in a food ends up being digested.

The starch that is not absorbed by the body is called resistant starch, and it is con- sidered dietary fiber.

It is also a source of nutrition for intestinal flora, which make important vitamins (and intestinal gas).

Starches are added to processed meats-lunch meats, hot dogs,

sausages, etc.-as fillers, binders, moisture retainers, and fat substitutes. They are added to soups, sauces, and gravies as thickeners. They are used in extruded cereals and snacks to hold the shape of the material.

Modified Starch

Starches can be modified in several ways to change their function as additives. They can be cross-linked, where the chains get stuck

Why There's Antifreeze in Your Toothpaste

together into a mesh. They can be heated to break the long chains down into simpler molecules like dextrin, polydextrin, and mal- todextrin. These are simply short starches. Starches can have a hydrogen replaced by something else, such as a carboxymethyl group, making carboxymethyl starch.

OH

... '0

OH

Carboxymethyl starch

OH

Adding the carboxymethyl group makes the starch less prone to

damage by heat and bacteria. Carboxymethyl starch is used as an addi- tive in oil drilling mud. It is also used in the goo that makes ultra- sound examinations so messy. Carboxymethyl starch is also called a starch ether.

Carboxymethyl groups make the starch more hydrophilic (water-

loving), and aid in cross-linking. This makes carboxymethyl starch useful in aspirin and other tablets to make them disintegrate quickly.

Longer carbon chains can also be added, such as carboxyethyl

groups, or carboxypropyl groups. Adding bulky functional com- ponents like carboxymethyl and carboxyethyl groups reduces the tendency of the starch to recrystallize. When the starch stays as a gel, a product is softer, and we refer to it as fresh. When the starch regains its crystalline form, the product becomes firmer, and we refer to it as stale. The technical term for this recrystallization is starch retrogradation. Starches can be esterified by modifications with an acid. An ester is the result of reacting an alcohol with an acid. The starch loses a hydroxyl group, and the acid loses a hydrogen. These combine to form water as the other product of the reaction.

Stabilizers and Thickeners

147 Using acetic acid, starch acetates are formed, which are used as film-forming polymers for pharmaceutical products, and as the poly- mer in biodegradable packing-foam peanuts. Starch acetates have a lower tendency to create gels than unmodified starch. Acids can also break the long chains into shorter molecules, much as heat does, to form polydextrins, maltodextrin, or dextrin. Enzymes are used to do the same thing.

Cross-linking occurs when a hydroxyl group (OH) on one chain

bonds with a hydroxyl group on an adjacent chain. This toughens the starch and helps it resist heat and acids. Cross-linking can be done by heating, or by reacting with compounds such as phosphates or glycerol. Starches are also sometimes pregelatinized to make them easier to dissolve during product manufacture. Starches, especially modified starches, are also used as glues in cardboard manufacturing. Starches such as gum arabic and gum tra- gacanth are used as the glue for stamps and postal envelopes. Oxidized starch, usually oxidized with sodium hypochlorite, is whiter than unmodified starch; it has increased clarity and lower viscosity.

Carrageenan

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

Seaweed extract

Description

White powder.

Carrageenan is a long-chain polysaccharide with a backbone of

the sugar galactose.

Uses

Carrageenan is widely used in dairy products because it forms com- plexes with calcium and milk proteins. It thickens and helps suspend cocoa particles in chocolate milk. It stabilizes ice cream to protect it from thawing and refreezing, and enables it to hold more air. It is used as a thickener in flans, custards, and puddings. It helps to keep whipped toppings foamy, and it thickens diet shakes and instant breakfast drinks. It is also used as a dough conditioner in breads and pastries.

Guar Gum

See entry, page 97.

Locust Bean Gum

See entry, page 101.

Brominated Vegetable Oil

Chemical Formula

IIo

Stabilizers and Thickeners

Synonyms

BVa

Description

Dense, oily liquid.

Uses

Brominated vegetable oil is ordinary oil, such as olive oil, that has had bromine added at various places to give the molecule the density of the sugar water in soft drinks. This allows Bva to keep citrus and other oil-based flavorings in solution without separating into an oil layer floating on top of the beverage. The result is the cloudy solution you see in orange-flavored or grapefruit-flavored soft drinks. The chemical formula depicted above is that of trilinolein, a rep- resentative component of vegetable oils. Bromine atoms attach at var- ious places on the molecule to form Bva. The amount of bromine is controlled to produce the desired density.

Gum Arabic

Chemical Formula

Polysaccharides and glycoprotein complex

Synonyms

Gum acacia· gum tragacanth (a similar gum) • gum karaya (also a similar gum) • gum ghatti (also a similar gum)

Description

White powder. Gum arabic is a complicated mixture of long and short chains of sugars (arabinogalactan oligosaccharides and polysaccharides) and glycoproteins (proteins with sugars attached). It is a powder that becomes a sticky glue or gum when mixed with water. It is extracted from the sap of the Acacia senegal and Acacia seyal trees native to the Sahara desert.

Why There's Antifreeze in Your Toothpaste

Uses

Gum arabic (gum acacia) is used as the lickable glue on stamps and envelopes, and as a flavor stabilizer (emulsifier) in soft drinks. It has components that bind to water, and components that bind to oils, making it an emulsifier but not a surfactant (because of the high molecular weight). It is used in hard candies and as a foam stabilizer in marshmallows.

The similar products gum tragacanth, gum karaya, and gum

ghatti are used in much the same way-as acid-resistant thickeners in sauces and salad dressings.

Xanthan Gum

See entry, page 102.

Dough

Conditioners and

Whipping Agents 14

What could be simpler than bread? Flour, water, salt, and yeast are all you need, right? But if you want to ship the bread across the country, store it on shelves for a while, and avoid having it go stale or moldy, you might want to consider getting a little help from some other foods and food products. Most of the long, scary-sounding chemicals listed on packages of supermarket bread are actually made from other foods; they are added to prevent the starch in the bread from changing, oxidizing, or becom- ing moldy.

Sodium Stearoyl Lactylate

Description

Off-white power. Sodium stearoyllactylate (and the similar calcium stearoyllacty- late) is made by combining lactic acid and stearic acid, and then react- ing the result with sodium hydroxide or calcium hydroxide to make the sodium or calcium salt. 151

Why There's Antifreeze in Your Toothpaste

Replacing the lactic acid with fumaric acid gives sodium stearoyl fumarate, a compound with the same uses as the other two.

Uses

Sodium stearoyl lactylate is an emulsifier that is used as a dough strengthener in baked goods. It has several features that combine to make it very popular with bakers. It maintains the texture of freshly baked bread by keeping the amylose starch in its gelled state and pre- venting its recrystallization. It makes the gluten in the bread stronger and more extensible, increasing the volume of the loaf. It disperses the fats in the bread, making it softer, which means less fat is needed. It absorbs water, allowing the baker to get 1 to 1.5 percent more loaves from the same ingredients, thus making each loaf less expensive to manufacture. Finally, it has a sweet taste, which means less sugar is needed.

Calcium Stearoyllactylate

See Sodium Stearoyl Lactylate entry, page 151.

Sodium Stearoyl Fumarate

See Sodium Stearoyl Lactylate entry, page 151.

Focus: Bread

The smell of a home-baked loaf, the taste of a flaky ~ crescent, the texture of a slice of whole-grain bread- all these experiences can come from very basic ingre- dients. The simplest breads are made from flour, water, yeast, and salt. This is fine for breads that are eaten the same day they are baked.

Things get a little more complicated when the bread is

required to last for days without going stale, to be inexpensive,

Dough Conditioners and Whipping Agents

153 and to be consistent at any time of the year with grain from any supplier.

Wheat flour contains starch and protein, which form the

structure of the bread. Two of the proteins in flour, gliadin and the enzyme glutenin, form the elastic protein gluten when water is added and the mixture is stirred. Kneading the bread stretches the gluten into elastic sheets that can fill with gas to form bub- bles, making the bread lighter in texture. Yeast supplies the gas. Yeast feeds on sugars in the flour and produces carbon dioxide gas and alcohol as waste products. The final ingredient, salt, is added to slow down the rate of fermentation of the yeast. This gives a baker a certain amount of control over the rising process, ensuring that the bread will have the desired texture and will cook evenly.

Flour

Wheat flour can be made from whole wheat, or the germ and bran can be separated from the endosperm, which is then ground into flour.

Without the fibrous bran and the oily germ, the resulting flour has fewer nutrients.

However, it will create a lighter-textured, higher-rising bread that will keep longer.

If flour is allowed to age for about a month, its natural yellow- ish color will fade to white due to the effects of oxygen.

This aging period can allow insects to spoil the flour, and is often elim- inated by adding bleaching agents, such as benzoyl peroxide.

Malted barley flour is often added to bread because it gives the yeast more nutrients-primarily sugars-and gives the bread a different taste.

Malting a grain is the process of letting the grain soak in water until it starts to sprout.

The young sprouting barley plant converts some of the starch in the barley endosperm into sugars.

The barley is then cooked or ground into flour, which stops the sprout from eating the sugars, leaving them available to the yeast.

Sometimes sugar or high-fructose corn syrup is added as a yeast nutrient, or to make the crust of the bread brown more easily.

Why There's Antifreeze in Your Toothpaste

Some breads contain flour made from soybeans, which gives

them added protein and a different texture. Soy flour absorbs water to make a gel, making the bread denser. Some of the nutrients lost when the wheat germ and bran are discarded are returned to the flour by adding small amounts of vitamins and minerals. Among the nutrients most commonly added are niacin, thiamine, riboflavin, folic acid, iron, and calcium. Vegetable oils are added to breads to shorten the strands of gluten and give the bread a more cakelike texture. Adding fats or oils also keeps bread from getting stale, which allows for storage of longer than one day.

How Bread Gets Stale

Stale bread tastes and feels dry, even though the moisture con- tent is actually the same as in fresh bread. The recrystallization of the starch in bread is what makes it go stale. To combat this, fats and oils are added to bread to form a complex with the starch in its gelled form, slowing down the recrystallization pro- cess and keeping the starch in its flexible gel form.

Fats and oils, however, interfere with gluten, making the

gluten strands shorter and thus preventing the loaf from increas- ing in volume. So emulsifiers are commonly used instead of fats to control staling. Emulsifiers have a fatty acid at one end that combines with the starch, as well as a water-loving end that helps to keep the starch dispersed in the dough. Emulsifiers aid in distributing fats and oils throughout dough, so less fat or oil is needed.

Some emulsifiers commonly used in baked goods are

• lecithin • sodium stearoyl lactylate • glycerol monostearate • diglycerides

Dough Conditioners and Whipping Agents

155 Another way to prevent bread from becoming stale is to add humectant (water-attracting) agents to the dough. To recrystal- lize, starch needs water. By attracting water away from the starch, humectants keep it from recrystallizing and at the same time add more moisture to the product. Moist bread tastes better and has better texture, and it weighs more without adding expen- sive ingredients. Thus, a one-pound loaf of bread with higher water content is less expensive than a drier one-pound loaf. Salt and sugar are good humectants. Sugars that are less sweet, such as dextrose (glucose), have excellent humectant properties.

Dough Conditioners

Bakers often use additives to change the dough in certain ways and give themselves more control over the baking process.

Some of these dough conditioners are

• sodium stearoyl lactylate • calcium dioxide • calcium iodate • potassium iodate • ammonium sulfate (yeast nutrient) • potassium persulfate (strong oxidizer used as a strengthen- ing agent) • ammonium persulfate (strong oxidizer used as a strengthen- ing agent) • calcium sulfate • ascorbic acid • amylase • azodicarbonamide • calcium propionate

Why There's Antifreeze in Your Toothpaste

Potassium Bromate

Chemical Formula

KBr03

Synonyms

Bromated flour· bromic acid· potassium salt

Description

White crystals or powder.

Uses

Potassium bromate is used as a flour improver. It strengthens the dough to allow for higher rising. It is an oxidizing agent, and under the right conditions it will be completely used up in the baking bread. However, if too much is used, or if the bread is not cooked long enough or at a high enough temperature, then a residual amount will remain. Potassium bromate has been banned in several countries as a car- cInogen.

Carrageenan

See entry, page 147.

Tetrasodium Pyrophosphate

See entry, page 46.

Fumaric Acid

See entry, page 66.

Stimulants

15 At one time, Coca-Cola actually contained a form of cocaine. These days, the primary stimulant in Coca-Cola and many other beverages is caffeine. Other stimulants are less obvious. Chocolate contains theo- bromine, a caffeinelike stimulant. Nondrowsy cold remedies contain pseudoephedrine, a relative of ephedra, another plant-alkaloid stim- ulant.

Caffeine

Chemical Formula

Synonyms

Trimethylxanthine

Why There's Antifreeze in Your Toothpaste

Description

White crystalline powder with a bitter taste.

Uses

Caffeine is an addictive drug used in soft drinks as a stimulant.

It occurs naturally in coffee, tea, and chocolate.

It is added to pain relievers because it enhances the effects of aspirin and because many headaches are caused by caffeine with- drawal.

Caffeine closes down blood vessels by competing with adeno- sine, and helps alleviate the vascular headaches caused by withdrawal.

A cup of drip-brewed coffee typically contains 100 milligrams of caffeine per 177 milliliters (6 ounces).

Tea has about 70 milligrams, and colas have about 50 milligrams.

A bar of milk chocolate has about 36 milligrams in 177 milliliters.

Caffeine binds to adenosine receptors in the brain, preventing adenosine from inducing sleep or opening blood vessels.

Caffeine also increases levels of dopamine, the neurotransmitter associated with pleasure.

This is the chemical mechanism for addiction.

The response to adenosine competition causes increased adrenaline flow.

Theobromine

Chemical Formula

Synonyms

Dimethylxanthine • 3,7-dihydro-3,7-dimethyl-1 H-purine-2,6-dione

Stimulants

Description

White crystalline powder with a bitter taste.

Uses

Theobromine is related to caffeine, but it has different effects in the body and brain. It is the mood-enhancing drug in chocolate. It is also the ingredient in chocolate that is toxic to dogs. The name theobromine means "food of the gods."

Ephedrine

Chemical Formula

OH

NH

...........

Synonyms

Pseudoephedrine· rna huang· ephedra· Mormon tea

Description

Ephedrine is the principal active ingredient in the herb ephedra, or rna huang. It is similar in form to the appetite-control drug phenyl- propanolamine (banned in the United States), which is also known as norephedrine, meaning ephedrine whose methyl group has been replaced by a hydrogen.

OH

Phenylpropanolamine (norephedrine)

Why There's Antifreeze in Your Toothpaste

It is also similar to the controlled stimulant amphetamine, which is norephedrine with the hydroxyl group replaced by a hydrogen.

Amphetamine

Methamphetamine

NH"

Pseudoephedrine is an isomer of ephedrine in which the hydroxyl group is on the other side of the molecule.

NH"

Pseudoephedrine

Uses

Ephedra is used in diet products as an appetite depressant and stim- ulant, and in sports drinks to mask fatigue. It is also used as a bronchial stimulator, and to relieve symptoms of the common cold.

Ephedrine enhances the release of the hormone norepinephrine

in the body, and also binds to the same receptors as that hormone, causing excess calories to be converted to heat instead of being stored as fat. It also raises blood pressure. Epinephrine and norepinephrine are also known as adrenaline and noradrenaline. Ephedrine thus acts to stimulate an adrenaline rush. Interactions with caffeine and aspirin can increase the effects of ephedrine. Norepinephrine works in part by increasing the levels of cyclic aminomethyl propanol (AMP) in cells. Caffeine inhibits the enzyme that breaks down cyclic AMP. Together, ephedrine makes more cyclic AMP, and caffeine prevents it from breaking down. Aspirin inhibits the receptors that turn off release of norepinephrine.

Stimulants

161 So ephedrine releases norepinephrine, and aspirin prevents the release from being turned off. Ephedrine by itself has been shown to be ineffective as a weight- loss treatment. Ephedrine combined with either caffeine or aspirin is effective. The effect appears to stem from a combination of appetite reduction and avoidance of the metabolic rate decrease usually asso- ciated with a reduced-calorie diet. Due to its effect as a stimulant on the heart and central nervous system, ephedrine can cause heart problems, stroke, and other med- ical complications (including death). For this reason, there has been pressure to regulate or ban it in the United States, as was done with similar drugs.

Medicines

16 We take aspirin to relieve pain, and sometimes to eliminate the cause of the pain, such as inflammation, fever, or joint swelling. We put germ killers on our skin, and we swallow pills to kill germs inside us. The chemistry of how these ingredients work in or on our bodies is the business of huge industries and large amounts of research.

Benzoyl Peroxide

Chemical Formula

(CeHsCO)202

Description

White or off-white needle-shaped water-soluble crystals.

Uses

Benzoyl peroxide is used as a bleaching agent in wheat flour, but its more familiar use is as a powerful acne medication that can lay claim

to the following benefits

Why There's Antifreeze in Your Toothpaste

• Like salicylic acid and resorcinol, it causes dead skin cells to slough off. • It kills the Propionibacterium acnes bacterium that causes acne pimples. • It has an anti-inflammatory effect that reduces pimples and the pain they cause. • It is a bleaching agent that oxidizes dyes to make them colorless. • It eliminates fatty acids on the skin. ~ Chemistry Lesson A peroxide is a compound that has an oxygen-oxygen bond.

That is, it has two oxygen atoms bound together.

Look again at the structural formula above.

The molecule is symmetrical, with two identical parts joined at their oxygen atoms with an oxygen-oxygen bond.

A familiar peroxide is hydrogen peroxide.

It has two oxygen atoms bound together, and each of those atoms in turn bind it to a hydro- gen atom.

Peroxides make good bleaches.

The oxygen atoms combine with dyes to make the dyes colorless.

This process, called oxidation, can kill germs.

Focus: Acne Medicines

Acne is caused when skin cells shed too quickly in hair ~ follicles. This clogs the follicle, producing comedones, ~ ~ more commonly known as whiteheads and blackheads. These can then become inflamed and turn into pimples.

Acne medicines may contain ingredients such as salicylic

acid, benzoyl peroxide, and sulfur, which remove the top layer of dead skin. They may also contain ingredients that have antibac- terial action. Some ingredients reduce sebum production; others reduce inflammation.

Medicines

Sulfur

Sulfur was once quite common in acne medications, but while it was effective at reducing inflammatory lesions, it caused more whiteheads and blackheads, from which the inflammatory lesions form. For this reason, it is usually combined with something like salicylic acid, or resorcinol, to eliminate the comedones.

Resorcinol

Resorcinol unclogs pores by causing dead skin cells to slough

off. It also has antifungal and antibacterial effects.

Benzoyl Peroxide

Benzoyl peroxide can help remove dead skin cells, which in turn prevents the pores from clogging up. It also kills the Propionibac- terium acnes bacterium that causes acne. It has anti-inflamma- tory effects and reduces oxygen free radicals and fatty acids on the skin.

Salicylic Acid

Salicylic acid unclogs the pores and reduces inflammation. It is also somewhat effective at killing bacteria.

Hydroxy Acids

Salicylic acid is a beta hydroxy acid. Glycolic acid is an alpha hydroxy acid, as are lactic acid, citric acid, and many others.

Hydroxy acids are compounds that are both alcohols and acids

at the same time. Hydroxy acids are used as chemical peeling agents. Alpha hydroxy acids can make the skin more sensitive to ultraviolet light by removing the skin's protective outer layers.

Some alpha hydroxy acids

• citric acid • lactic acid • ammonium glycolate • alpha-hydroxycaprylic acid

Why There's Antifreeze in Your Toothpaste

• alpha-hydroxyethanoic acid • alpha-hydroxyoctanoic acid • glycolic acid (sometimes called fruit acid or sugar cane extract) • malic acid

Salicylic Acid

Chemical Formula

CSH4(OH)C02H

OH

Synonyms

2-hydroxybenzoic acid

Description

White odorless crystals.

Uses

Salicylic acid is used to treat acne, warts, dandruff, psoriasis, and sim- ilar conditions. In the treatment of acne, it slows the shedding of skin cells in hair follicles, so they do not clog the pores and cause pimples. It also has a keratolytic effect-it causes dead skin cells to slough off- which removes the top layer of skin and clears existing pore clogs. In treatments for warts, a stronger solution is used. Not only does this soften the wart so it can be rubbed off, but the irritation also stim-

Medicines

167 ulates the immune system to attack the underlying cause of warts, human papillomavirus. Salicylic acid reacts with acetic acid to produce acetylsalicylic acid the active ingredient in aspirin. It also reacts with methanol to form methyl salicylate, more commonly known as oil of wintergreen. Salicylic acid is common in foods such as broccoli, peppers, curry, cucumbers, and raisins, among many others. Salicylic acid reduces inflammation, including inflammation ofthe arteries. In arteries it can work to prevent hardening and narrowing.

Sulfur

Chemical Formula

Description

Yellow crystals or powder.

Uses

Sulfur is used in acne medications to treat inflamed lesions (pimples). It can cause whiteheads and blackheads (comedones) if used by itself, so it is usually combined with salicylic acid, benzoyl peroxide, or resorcinol, which eliminates comedones.

Resorcinol

Chemical Formula

CSH4(OH)2

HO

Why There's Antifreeze in Your Toothpaste

Synonyms

M-dihydroxybenzene

0 1,3-benzenediol o 3-hydroxyphenol

Description

White or off-white needle-shaped water-soluble crystals.

Uses

As an acne treatment, resorcinol has a keratolytic effect-it causes dead skin cells to slough off-which removes the top layer of skin and unclogs pores. It is often used with sulfur, to prevent the whiteheads and blackheads that may be a side effect when sulfur is used to treat inflamed pimples. Like salicylic acid, it is also used to treat warts, psoriasis, and other skin conditions.

Hydrogen Peroxide

Chemical Formula

H20 2

I0-0

Description

Clear, colorless liquid.

Uses

Hydrogen peroxide is used as a topical antiseptic in dilute solutions, and as a water purifier in stronger solutions. It is also famous as a hair bleach. Hydrogen peroxide breaks down into water and oxygen. A liter of 3 percent hydrogen peroxide will generate 10 liters of oxygen when a catalyst is used to facilitate the breakdown. Catalysts can be metals such as iron, copper, or silver, or organics such as the blood enzyme

Medicines

169 catalase (like hemoglobin, catalase contains iron, which catalyzes the reaction). Catalase is an important enzyme in cells because hydrogen per- oxide is a by-product of metabolism and can poison the cell unless it is decomposed quickly. Hydrogen peroxide is also produced by cells in the immune system, and catalase removes the excess. The 3 percent hydrogen peroxide you get at the drugstore is often protected from decomposing by the addition of sodium silicate, mag- nesium sulfate, or tin compounds. These stabilizers lock up the iron, copper, and other transition metals that can act as catalysts.

Sodium Bicarbonate

Chemical Formula

NaHC03

Synonyms

Bicarbonate of soda· baking soda

Description

White powder.

Uses

Sodium bicarbonate is used as a leavening in breads, as a stomach antacid, as a buffering agent to adjust the acidity or alkalinity of a product, as a mild abrasive in toothpaste, and as an odor absorber. Sodium bicarbonate reacts with acids to release carbon dioxide gas.

Hydroquinone

Chemical Formula

OH

Why There's Antifreeze in Your Toothpaste

Description

Off-white powder or white needlelike crystals.

Hydroquinone inhibits melanin production when applied to the

skin. The effect is reversible by exposure to ultraviolet light.

Uses

Hydroquinone in a 2 percent solution is used in many skin-lighten- ing creams and gels to remove freckles, age spots, and other hyper- pigmented areas of the skin. Since sunlight reverses the effect, a sunscreen is usually mixed into the preparation.

Antibiotics

Triclosan

See entry, page 25.

Triclocarban

See entry, page 25.

Hexachlorophene

See entry, page 26.

Pain Relievers

Potassium Nitrate

Chemical Formula

KN03

Synonyms

Saltpeter

Medicines

Description

White crystals.

Uses

Potassium nitrate is best known as the oxidizing agent in old-fash- ioned "black powder" gunpowder, which is 75 percent potassium nitrate by weight.

The other ingredients are 15 percent charcoal and 10 percent sulfur.

But potassium nitrate is also used in toothpastes that are formu- lated to make teeth less sensitive to pain.

As gums recede and the tooth root dentin becomes exposed, teeth can become hypersensitive to hot or cold foods.

Potassium nitrate interferes with the transmission of pain signals in the nerves of the teeth.

Potassium nitrate is also found in pills for backache and joint pain.

It makes a decent plant fertilizer, providing nitrogen and potas- sium but no phosphorus.

As an oxidizer, it is an ingredient in stump removers that hastens the decay of tree stumps.

And it is used as a pre- servative in some salted meats; like nitrites, it helps to preserve the color of the meat.

Benzocaine

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

Ethyl p-aminobenzoate • ethyl PABA· anesthesin

Description

White crystalline powder.

Uses

Benzocaine is a topical anesthetic. It numbs any area to which it is applied. It is widely used in first-aid creams and sunburn remedies. ~ Chemistry Lesson Benzocaine is an ester, a compound made from the organic acid PABA (para-amino benzoic acid) and the alcohol ethanol.

OH

Para-amino benzoic acid

Other esters of PABA have similar anesthetic properties.

Medicines

Procaine (novocaine)

Dentists use procaine (also called novocaine) to numb teeth and gums before dental work.

Lidocaine (xylocaine)

Another topical anesthetic, similar to benzocaine, is lidocaine, which is used to relieve the pain of shingles (herpes zoster) infections. Lidocaine is called an amide anesthetic, because it is not an ester (the alcohol is replaced by an amide, the nitrogen group). Amide anes- thetics are metabolized by the liver, and are less prone to cause aller- gic reactions. If an anesthetic has the letter i in the prefix (lidocaine, prilocaine, bupivacaine), it is an amide anesthetic.

Why There's Antifreeze in Your Toothpaste

O""'IN.~

NH

Denatonium benzoate

A small change to lidocaine (adding a benzyl group) makes the molecule denatonium benzoate, the bitterest tasting substance known. It is used to denature alcohol-to make it unfit for drinking. Specially denatured alcohol 40, or 50-40, is ethanol denatured (made unfit for drinking) by a tiny amount denatonium benzoate. 0- o

II

oJJ\ 0-

'---I

Cocaine hydrochloride

You can see a resemblance between benzocaine, procaine, and the compound that gave Coca-Cola its first name. Cocaine also has a

Medicines

175 numbing effect, in addition to its effects as an addictive central nerv- ous system stimulant. Some other anesthetics with similar structures are prilocaine,

tetracaine, ropivacaine, bupivacaine, chloroprocaine, and mepivacaine

NH

Prilocaine

Tetracaine

Why There's Antifreeze in Your Toothpaste

NH

Ropivacaine

N~

NH

Bupivicaine

Chloroprocaine

Mepivacaine

o~~

CI

Medicines

Why There's Antifreeze in Your Toothpaste

Tramadol

Chemical Formula

Hel

o \

Synonyms

(+/-)cis-2-((dimethylamino)methyl) -1-(3-methoxyphenyl)-cyc1o- hexanol hydrochloride

Description

White, odorless, bitter crystalline powder.

Uses

Tramadol is a pain reliever (analgesic). Its action is similar to opioid narcotics such as codeine and morphine, but it does not depress breathing the way the others can, and less often leads to abuse and addiction. ~ Chemistry Lesson Tramadol is an alkaloid, with an amine group (where the nitrogen atom is), which puts it in a group of bitter plant chemicals that often have potent biological activity. Alkaloids range from the belladonna alkaloids, such as atropine and scopalomine-which are used as poisons, cold remedies, and "truth serums"-to dextromethorphan, a cough suppressant (anti- tussive). But the most widely known alkaloids are the opiates, such as morphine, heroin, fentanyl, oxycodone, and methadone. These act on

Medicines

179 receptors in the brain that are normally activated by small proteins (peptides) called endomorphins or endorphins.

Atropine

-0

OH

Codeine

Fentanyl

Why There's Antifreeze in Your Toothpaste

HO

Morphine

o //0 \ o --:..;...11_0

Heroin

-0

Dexlromelhorphan

Oxycodone (OxyContin)

Medicines

HO

Buprenorphine

Acetylsalicylic Acid

Chemical Formula

CSH4(OCOCH 3)C02H

O~

Why There's Antifreeze in Your Toothpaste

Synonyms

Aspirin· 2-acetoxybenzoic acid

Description

White odorless crystals.

Uses

Acetylsalicylic acid is more commonly known as aspirin. It is used as a pain reliever, fever reducer, and anti-inflammatory. Acetylsalicylic acid breaks down into salicylic acid 20 minutes after entering the bloodstream. It is the salicylic acid that is responsi- ble for the beneficial effects of aspirin. Salicylic acid itself is too caus- tic to be taken orally. Acetylsalicylic acid has an anticlotting effect in the blood.

Acetaminophen

Chemical Formula

CBHBN02

°O

OH

II

/"--- N

Synonyms

Tylenol· paracetamol • N-acetyl-para-aminophenol • para-acetyl- amino-phenol

Description

Bitter white powder.

Uses

Acetaminophen is a pain reliever similar to aspirin, but it does not have aspirin's anti-inflammatory properties-or its undesirable effects

Medicines

183 on the stomach lining. It also lacks aspirin's anticoagulatory effects. Acetaminophen is often combined with opiates such as codeine and dihydrocodeine to form a more potent painkiller. Unlike aspirin and other cyclooxygenase inhibitors that work on the COX-l and COX-2 enzymes, acetaminophen works on the COX- 3 enzyme, which is present in the spinal column and brain. This helps it to avoid shutting down prostaglandin function elsewhere in the body, which is why it has no anti-inflammatory effects and does not affect blood platelets or the stomach lining.

Ibuprofen

Chemical Formula

C'3H'B02

HO

Synonyms

Advil

Description

White powder.

Uses

Like aspirin, ibuprofen is a nonsteroidal anti-inflammatory drug. It is a cyclooxygenase inhibitor that interferes with COX-l and COX-2 forms of that enzyme. Its effects on COX-2 give it fever-reducing (antipyretic), analgesic (pain relief), and anti-inflammatory functions.

Why There's Antifreeze in Your Toothpaste

Its effects on COX-l give it several undesirable effects: it is an antico- agulant, and it irritates the stomach lining. Ibuprofen is used to relieve fever and pain, and symptoms of arthritis and menstrual cramping. It may also reduce the dizziness associated with standing up quickly (called orthostatic hypotension), and some studies have shown that it may have beneficial effects for patients suffering from Alzheimer's disease and Parkinson's disease.

Naproxen

Chemical Formula

C14H1403

""0

OH

Synonyms

Aleve'naproxen sodium

Description

White powder.

Uses

Like aspirin, naproxen is a nonsteroidal anti-inflammatory drug. It is a cyclooxygenase inhibitor that interferes with COX-l and COX-2 forms of that enzyme. Its effects on COX-2 give it fever-reducing (antipyretic), analgesic (pain relief), and anti-inflammatory functions. Its effects on COX-l give it several undesirable effects: it is an antico- agulant, and it irritates the stomach lining. Naproxen is used to relieve fever, pain, and symptoms of arthri- tis, gout, bursitis, and menstrual cramping. Naproxen has been found to increase the risk of heart attack and stroke by 50 percent.

Medicines

Allantoin

Chemical Formula

C4HsN40 3

Synonyms

Glyoxyldiureide • comfrey root extract

Description

White, odorless, tasteless crystals or powder.

Uses

Allantoin relieves the skin irritation caused by soaps and detergents, acids, and alkalies in oral- and skin-care products.

Some studies claim that it promotes wound healing and tissue

formation, but regulatory agencies do not credit these claims.

Menthol

See entry, page 59.

Methyl Salicylate, Ethyl Salicylate, Glycol Salicylate

Chemical Formulas

CBHB0 3• C9HlON03 • and C9HlO0 4

Methyl salicylate

Why There's Antifreeze in Your Toothpaste

H0Y'n

II°

Ethyl salicylate

H0Y'n

~O~

HO

II

Glycol salicylate

Synonyms

Oil of wintergreen· salicylic acid· methyl ester· methyl sweet birch oil· betula oil

Description

Reddish or yellow liquid.

Uses

Wintergreen is used as a flavoring in foods, beverages, drugs, and can- dies. It is also used as a perfume in root beer, and as an ultraviolet light absorber in cosmetics. It serves as a pain reliever in liniments and ointments. It is a rube- facient, meaning that it can dilate blood vessels. The most widely used salicylate is aspirin.

Medicines

Camphor

Chemical Formula

C1QH 160

Synonyms

2-camphanone· 1,7,7-trimethylbicyclo[2.2.1] -2-heptanone

Description

White crystals.

Uses

Camphor is a rubefacient-it relieves mild pain and itching, and cre- ates inflammation and redness when rubbed into the skin. Much like menthol, it has a cooling effect when applied to the skin. Camphor is used in acne medications, cough remedies, ear drops, and other medications where its ability to soothe the skin helps it to counter the effects of other ingredients that might otherwise be irri- tants.

Methyl Nicotinate and Benzyl Nicotinate

Chemical Formula

C7H7NOz and C13H11NOz

Methyl nicotinate

Why There's Antifreeze in Your Toothpaste

Benzyl nicotinate

Synonyms

Niacin methyl ester· nicometh • 3-carbomethoxypyridine • methyl 3- pyridinecarboxylate • 3-pyridinecarboxylic acid· methyl ester

Description

White crystalline powder and yellow liquid.

Uses

The B vitamin niacin is also known as nicotinic acid. The body con- verts various forms of the vitamin into forms it can use. The methyl ester and benzyl ester forms can be used as a rubefa- cient (a vasodilator that opens up capillaries, which as a side effect makes the skin redden). It also works to reduce plasma cholesterol. Niacin is recommended to alleviate pellagra, a disease caused by a deficiency of this vitamin.

Capsaicin

Chemical Formula

C1sH27N03

HO

Medicines

Synonyms

8-methyl-N-vanillyl-6-nonenamide· capsicum oleoresin

Description

Colorless, odorless waxy crystals.

Uses

Capsaicin is what makes chili peppers hot. It is an irritant.for mam- mals, but not for birds. This may be because birds spread the seeds better than mammals. It causes a burning sensation in any mam- malian tissue with which it comes in contact. Capsaicin is a nonpolar molecule; it dissolves in fats and oils, not in water. This is why water does not take away the burning sensation, but whole milk or other fat-containing liquids or foods will. As an ingredient in medicines, capsaicin is used to relieve pain from arthritis, muscle aches, and sprains. It is a rubefacient, meaning it dilates blood vessels. The heat effect overwhelms nerves, causing a localized numbing sensation. Capsaicin is also used in pepper spray.

Bleaching Agents

17 Sometimes rather than adding color to a product, it is necessary to take color away. We bleach our clothes, our hair, and sometimes even our food. Most often chemicals react with colorful compounds to make them colorless through a process called oxidation.

Sodium Hypochlorite

Chemical Formula

NaDGI

Synonyms

Chlorine bleach

Description

Sodium hypochlorite is usually sold in solution in water, where it makes a greenish-yellow liquid. (It is too hygroscopic-it absorbs water from the air-to be used conveniently in solid form.) Household bleaches usually contain sodium hypochlorite in a 3 percent to 6 percent solu- tion. Some sodium hydroxide (lye) is added to keep the pH high to avoid decomposition. If the solution is made more acidic, sodium hypochlorite will dissociate, producing chlorine gas and oxygen.

Sodium hypochlorite is made by bubbling chlorine gas through

a solution of sodium hydroxide. In the environment, it breaks down into water, oxygen, and table salt. 191

Why There's Antifreeze in Your Toothpaste

Uses

Sodium hypochlorite is the main ingredient in laundry bleach. Despite the fact that it is commonly referred to as chlorine bleach, in normal use there is no chlorine gas involved in the action of bleach- ing or disinfecting. Sodium hypochlorite is one of the best disinfectants known, capa- ble of killing bacteria, yeasts, fungus, spores, and even viruses. Because it is an excellent disinfectant as well as a bleaching agent, it is used in many household cleaners. Sodium hypochlorite is also used to disin- fect water supplies and swimming pools (although calcium hypochlo- rite in powder or pellet form is often used as a substitute, due to the convenience of its solid form).

Focus: Bleach

We bleach our clothes. We bleach our hair. We bleach our teeth. We bleach our skin. We bleach our food. We use bleaches to disinfect and deodorize. Some bleaches smell awful. Some, like lemon juice and sunshine, are refreshing. Here are a few things you should know about bleach.

Color and Bleach

Colored substances contain molecules with chromophores, areas

of the molecule that have double bonds between carbon atoms or oxygen atoms. A good example is beta-carotene, and that section goes into more detail on how molecules become colored. Bleaches attack these chromophores in one of two ways.

First, oxidizing bleaches such as sodium hypochlorite break

the molecules at the double bond. This results in either a shorter molecule that does not absorb visible light, or a molecule whose chromophore is either shorter or nonexistent. A shorter chro- mophore will absorb light of a shorter wavelength than visible light (such as ultraviolet light), and so does not appear colored.

Bleaching Agents

Second, reducing bleaches such as lemon juice (in combina-

tion with sunlight) or sulfur dioxide convert the double bonds in the chromophore into single bonds, eliminating its ability to absorb visible light. Sometimes the reaction is reversible, where oxygen in the air reacts with the molecule to repair the chro- mophore, and the stain returns.

Bleaching Clothing

Laundry bleaches fall into two categories. The first is what are called chlorine bleaches. The second is oxygen bleaches.

While pure chlorine gas will certainly bleach colors, laundry

bleaches use sodium hypochlorite or calcium hypochlorite, which works by releasing oxygen, not chlorine. The chlorine remains in solution, either as sodium chloride (table salt), or calcium chloride. These bleaches are made by bubbling chlorine gas through a solution of sodium hydroxide (lye) or calcium hydroxide (quicklime). If the bleach is mixed with an acid, it can release poisonous chlorine gas. To prevent this from happening, commercial bleaches leave extra alkalies in the solution to keep the pH very high (pH 12). This small amount of extra lye in the solution, along with the caustic nature of the hypochlorite itself, is what eats away the cloth if undiluted bleach gets spilled on the clothing.

Another chlorine bleach in common use is sodium

dichloroisocyanurate. Oxygen bleaches also work by releasing oxygen. Hydrogen peroxide is the active ingredient, either as itself or as a product of reacting another ingredient with water to release hydrogen peroxide.

Oxygen bleaches such as sodium carbonate peroxide (also

called sodium percarbonate), sodium peroxide, or sodium perbo- rate are made by reacting molecules with hydrogen peroxide. When the result is added to water, the hydrogen peroxide is released.

Borax also works by releasing hydrogen peroxide into the

water.

Why There's Antifreeze in Your Toothpaste

Most oxygen bleaches work best in hot water. Additives such as tetra acetyl ethylene diamine allow the hydrogen peroxide to work in warm water (50°C).

Bleaching Hair

Ultraviolet light from the sun is the most common hair-bleaching agent. Lemon juice is sometimes added to speed up the process of reducing the double bonds in hair pigments to single bonds. However, the most famous hair bleach is hydrogen peroxide. Unlike sunlight and lemon juice, peroxide is an oxidizing bleach, and its effects are less easily undone.

The calcium hypochlorite or sodium dichloroisocyanurate

used to disinfect swimming pools also bleaches hair, although contrary to popular belief it does not turn the hair green. It simply allows the green copper sulfate from the water to show up in the hair. The copper sulfate comes from the reaction of the copper pipes in the plumbing to the sulfuric acid used to neutralize the alkalies in the chlorination chemicals.

Bleaching Teeth

Dental bleaches are an ingredient in whitening toothpastes and in whitening gels or strips applied to the teeth. Whitening tooth- pastes most often use sodium carbonate peroxide. In gels and strips, carbamide peroxide is used, often with tetra acetyl ethyl- ene diamine as a bleach activator. All of these products owe their bleaching action to the hydrogen peroxide that is liberated during application.

Bleaching Skin

Skin lighteners, freckle and age spot removers, and other reme- dies for hyperpigmentation are not actually bleaches like the products listed so far. The active ingredient is hydroquinone, which inhibits melanin formation when applied to the skin. Since the effect is easily reversed by exposure to sunlight or ultraviolet light, a sunscreen is usually included in the formula.

Bleaching Agents

Bleaching Food

Wheat flour typically becomes white by means of normal oxida-

tion in air during a few weeks of storage. To speed up the pro- cess, manufacturers use benzoyl peroxide as a bleaching agent. Sulfur dioxide is a reducing bleaching agent that is used to pre- serve dried fruits.

Disinfecting

OXidizing bleaches kill microbes by reacting with cell membranes and cell proteins. The most widely used is sodium hypochlorite for household and hospital uses, and calcium hypochlorite for drinking water and swimming pool disinfecting.

Calcium Hypochlorite

Chemical Formula

CaGCI

Synonyms

Chlorine tablets

Description

White powder or tablets. It is made by bubbling chlorine gas through a solution of calcium hydroxide.

Uses

Calcium hypochlorite is the main ingredient in swimming pool chlo- rine tablets. Calcium hypochlorite is one of the best disinfectants known; it kills bacteria, yeasts, fungus, spores, and even viruses. It is more com- monly used to disinfect water supplies and swimming pools than its close cousin sodium hypochlorite (household bleach) because it can be sold as a solid (it does not attract moisture from the air and clump up as sodium hypochlorite powder does).

Why There's Antifreeze in Your Toothpaste

Hydrogen Peroxide

See entry, page 168.

Benzoyl Peroxide

See entry, page 163.

Borax

Chemical Formula

Na2B40 7

Synonyms

Sodium borate decahydrate • sodium tetraborate decahydrate •

sodium biborate • sodium pyroborate

Description

White powder.

Uses

Borax is used in laundry detergents and bleaches. It releases hydrogen peroxide when it reacts with water. Hydrogen peroxide acts as a bleach, and its action is aided by the alkaline solution also produced by the reaction. Borax is a good buffer, helping to stabilize the acidity or alkalin- ity of a solution. The boron (along with the oxygen and salt) in a borax solution helps to disinfect by killing bacteria and fungi.

Sodium Perborate

Chemical Formula

NaB03

Description

White powder.

Bleaching Agents

Uses

Sodium perborate is used in laundry detergents and bleaches. It releases more hydrogen peroxide than borax when it reacts with water. Hydrogen peroxide acts as a bleach, and its action is aided by the alka- line solution that is also produced by the reaction.

Sodium Carbonate Peroxide

Chemical Formula

2Na2C03 . 3H 20 2

Synonyms

Peroxy sodium carbonate· sodium percarbonate

Description

White granules.

Uses

Sodium carbonate peroxide breaks down into sodium carbonate and hydrogen peroxide. The hydrogen peroxide acts as a bleach and as an antimicrobial agent. The high alkalinity of the sodium carbonate boosts the bleaching effect of hydrogen peroxide.

Sodium Dichloroisocyanurate

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

Sodium chlorocyanurate • 1,3-dichloro-l ,3,S-triazine-2,4,6( 1H,3H,

SH)-trione sodium salt· sOle

Description

White powder with a strong chlorine odor.

Uses

Sodium dichloroisocyanurate is used as a disinfectant in swimming pools and as a bleaching agent in household cleansers.

Hydroquinone

See entry, page 169.

Surfactants

18 To remove fats, oils, and grease from our clothes, our hair, our bod- ies, and our dishes, we use products known as surfactants. These con- tain ingredients that make oil and water mix, forming tiny droplets out of oil slicks, so the droplets can be washed away in the rinse water.

Ammonium Lauryl Sulfate

Chemical Formula

CH3(CH2)lOCH20S03N H4

0=8=0

NH4+

Synonyms

Dodecyl ammonium sulfate

Why There's Antifreeze in Your Toothpaste

Description

Light yellow viscous liquid.

Uses

Ammonium lauryl sulfate is an anionic surfactant. This means it low- ers the surface tension of water, making the water spread more easily. Surfactants are also called wetting agents-in plain terms, they make water wetter. Ammonium lauryl sulfate is added to products as a foaming agent and as a detergent. Notice in the structural formula that one end of the molecule is a long chain of carbon and hydrogen, while the other end is a salt of sulfuric acid and ammonia. The long chain is hydrophobic, and the salt is hydrophilic, making this a good deter- gent and surfactant. Ammonium lauryl sulfate is used in many shampoos, toothpastes, and skin cleansers. Unlike soap, it can be used in hard water.

When ammonium lauryl sulfate is reacted with ethylene oxide,

the result is the larger molecule ammonium laureth sulfate. This mol- ecule has the same detergent and surfactant qualities, but it is larger; consequently it does not penetrate the skin and hair as easily. The term laureth is actually a contraction of lauryl ether. The full name is ammonium lauryl ether sulfate. Sodium lauryl sulfate is the same compound and has the same uses, but in this case the ammonium group has been replaced with a sodium atom.

Focus: Shampoo

§1

Television would have you believe that shampoo will change

1'11III

your love life, make you suave and sophisticated, or fill . you with awe at how shiny your hair has become. ,. v

Shampoo

The purpose of a shampoo is to clean hair. But the shampoo must not clean too well, or all of the protective oils in the hair will

Surfactants

201 be stripped out. It must also not make the hair smell bad, despite the bad smells of the detergents it is made of. To sell well, the shampoo must look good, must feel thick or creamy in the hands, and must produce a nice-feeling lather. It must smell good, and it must not be too expensive. Other selling points might be the currently popular herbal extracts, or amino acids from exotic protein sources such as silk or the milk of pygmy goats.

Detergents

The most common ingredient in shampoos is also the most com- mon detergent in use in other products: a class of surfactants known as straight-chain alkyl benzene sulfonates. Examples are ammonium lauryl sulfate, its sodium relative, and the slightly larger but related molecule ammonium lauryl ether sulfate (some- times abbreviated as ammonium laureth sulfate).

These detergents work best in water that has little calcium

and magnesium, as these elements bind to the detergent and make an insoluble scum. Tetrasodium EDTA often is used to sequester the calcium and magnesium from the detergent, while keeping them soluble enough to rinse away without scum. Cocamide DEA (or MEA or TEA) is used as a foaming agent, to make lather. The other surfactants generate a certain amount of suds, but this foaming agent is added to get the amount just right. In addition to its foam-stabilizing effects, it is also a viscos- ity booster-it's thick.

Another foam stabilizing detergent is PEG-5 cocamide, which

is also a surfactant and emulsifier.

The detergent cocamidopropyl betaine is added because it is

milder on the skin than the benzine sulfonates, which means that adding it to the mix reduces the amount of the harsher deter- gents needed. It is thicker than the other ingredients, so it can be added to give the mix the right viscosity. It has antistatic proper- ties; it helps keep the hair from generating an electric charge when it's dry and jumping to plastic combs and brushes. It is also a humectant, attracting moisture from the air, thus keeping hair

Why There's Antifreeze in Your Toothpaste

from drying out. And it has antibiotic properties that can prevent the shampoo from spoiling.

The surfactant ammonium xylenesulfonate is used as both a

thickener and a hydrotrope, a compound that makes it easier for water to dissolve other molecules. It helps keep other ingredients in solution, including some of the odd substances that are added for marketing effect, such as perfumes. Glycerol stearate is another emulsifier used for this purpose.

Special Effects

The wax glycol distearate is added to make shampoos opaque

and pearlescent. It has tiny flakes that mix well with surfactants, and stay in solution. They also add shear-thinning qualities, mak- ing liquid hand soaps pump out of the bottle more easily. Sodium chloride (table salt) is used to thicken the mixture if the main surfactants are sodium lauryl sulfates. If the surfactants are ammonium-based, then ammonium chloride is used instead. Salt can make the shampoo harsh, which can sting the eyes, so more expensive thickeners are used to keep the salt levels low.

Modified cellulose-based thickeners are often used, along

with the surfactant-based thickeners already mentioned.

Glycerin is added as a humectant (draws moisture from the

air), as is propylene glycol, which is also a preservative.

There are many additives in shampoos and conditioners that

appear to be there mainly for marketing purposes. Honey, vari- ous herb extracts, and other compounds might add to the fra- grance, but they are unlikely to have any other effects in the small concentrations used. Amino acids can act as conditioners, but the source of the amino acid is not important. Silk amino acids are essentially no different from soy amino acids.

Preservatives

Two widely used preservatives, DMDM hydantoin and imidazo-

lidinyl urea, are ingredients used in many shampoos to prevent fungal and bacterial spoilage. They release formaldehyde to kill germs.

Surfactants

Other broad-spectrum biocides are isothiazolinone and the

closely related methylisothiazolinone and methylchloroisothiazoli- none. Sodium benzoate is another preservative used in shampoos. It kills bacteria, fungi, and yeasts, and works well in acidic mix- tures.

Another commonly used bactericide is 2-bromo-2-nitro-

propane-1 ,3-diol. pH Balance The surface of a strand of hair is covered with overlapping sheets, somewhat like the scales on a fish or the shingles on a house. This surface is called the cuticle. Alkaline solutions raise these scales, so they stand up. This makes the hair shafts stick together, which in turn makes the hair look and feel rougher and duller.

Most shampoos are made slightly acidic, to keep the cuticle

smooth and lying flat on the hair shaft. Ingredients like citric acid are added to acidify the shampoo. As shampoo is applied to the hair and scalp, it can become less acidic as the acids mix with alkaline water or dirt. A com- pound that releases more acidifying ions when the acidity gets low or absorbs acid when the acidity gets too high is called a buffer. A typical buffering agent used in shampoo is sodium citrate. Since the goal is to keep the shampoo slightly acid, the term "pH balanced" is actually a misnomer. You actually want the balance to be tipped slightly to the acidic side.

Conditioners

Conditioners are compounds added to keep the hair cuticle

smooth and slippery. Silicone oils such as dimethicone and cyclomethicone are used to make the hair shiny and slippery. Humectants (moisturizers) like panthenol help keep the cuticle moist so that the scales do not stand up. Long-chain fatty alco- hols such as cetyl alcohol, oleyl alcohol, and stearyl alcohol

Why There's Antifreeze in Your Toothpaste

lubricate the hair. One end of the molecule binds to the hair, leaving the slippery fatty end on the outside to rub against other strands of hair or a comb.

Quaternary ammonium compounds are cationic surfactants

that bind well to anionic surfaces like the protein in hair. The ammonium end sticks to the hair, leaving the long fatty end of the molecule to act as a lubricant. They are slightly conductive, so they reduce the buildup of static electricity. Quats, as they are sometimes called, include compounds like stearalkonium chlo- ride, disteardimonium chloride, quaternium-5, or quaternium-18, polyquaternium-10 and they are all similar in form and function to cetrimonium chloride. These compounds are also widely used as fabric softeners, for all of the same reasons they make good hair conditioners. They are also used to thicken the shampoo.

The emollient isopropyl palmitate is used as a skin softener,

moisturizer, and antistatic agent.

Sodium Lauryl Sarcosinate

Chemical Formula

CH3(CH2)10CH2C3HsNNa02

Description

Light yellow viscous liquid.

Uses

Sodium lauryl sarcosinate is very similar to the lauryl sulfate class of detergents and surfactants. The sulfate group is replaced with the amino acid sarcosinic acid, and the ammonium group is replaced with a sodium atom. The result is a detergent that is milder on the skin and oral membranes, and can be used in toothpastes without causing irri- tation of the gums.

Surfacrants

Lauryl Glucoside

Chemical Formula

OH

f-o, °

H~b-

OH

HO

OH

Synonyms

Lauryl diglucoside

Description

Viscous liquid. Lauryl glucoside (lauryl diglucoside) is a surfactant and detergent made from coconut oil (the "lauryl" part) and sugar (the "glucose" part). Such alkyl glycosides biodegrade quickly, and tend to be gentle to the skin, and they work in hard water.

Uses

Lauryl diglucoside is used in shampoos as a detergent and as a thick- ening agent.

Cocamidopropyl Betaine

Chemical Formula

/'...

/'... I/'.../'OH

ONH'

...... N/

IIo

Synonyms

Inner salt· coco betaine

Why There's Antifreeze in Your Toothpaste

Description

Pale yellow transparent liquid.

Uses

Cocamidopropyl betaine is an amphoteric detergent, a detergent that can act as an acid or a base. It does not irritate the skin or mucous membranes. It is used to thicken shampoos, and to reduce the irrita- tion that would result if only more irritating detergents were used. It has antibiotic effects, and is used in personal sanitary products. It also has antistatic properties, making it an effective conditioning agent in shampoos.

Sodium Stearate

Chemical Formula

CH3(CH2)16COONa

II

ONa

Synonyms

Soap

Description

Sodium stearate is one of the main compounds in common soap. To make soap, you start with beef fat. If you treat beef fat with steam you

get tallow, a mixture of fats, one of which is glyceryl tristearate

II

o o o

Surfactants

207 a triglyceride containing three stearic acid molecules attached to a glycerin molecule. When you boil glyceryl tristearate in lye (sodium hydroxide), you get sodium stearate and glycerin. When you remove the glycerin, you get soap. The sodium end of the molecule attracts water. The long hydro- carbon chain at the other end attracts oils and fats.

Uses

Soap works by helping to break fat and oil droplets into small pieces. The pieces are coated with the soap, with the hydrocarbon chains attached to the fat, leaving the sodium ends dangling in the water. The oils are now completely surrounded by water, instead of being attached to skin or clothing, and so they rinse away easily.

Focus: Soap

We like to be clean. Clean feels good. It smells good.

EV

Clean means fewer microbes are around to hurt us.

..:;-Clean clothes fe~1 good. Clean dishes make food safer ,/?" . and more attractive. , :r-~_

For thousands of years, soap was the last word in

clean.

Soap

The first soaps were probably the saps of plants such as Chloro- galum pomeridianum, the roots of which can be crushed in water to form a lather. Other plants, such as soapbark (Quillaja saponaria), soapberry (Sapindus mukoross/), and soapwort (Saponaria officinalis) also contain the same main ingredient, a compound called saponin, which forms the foamy lather. (Saponin can also be used in fishing; a toxin, it is introduced into streams to stupefy fish and make them easy to catch.) Later, people learned that fats would react with alkalies in the ashes left over from a fire to produce saponified compounds

Why There's Antifreeze in Your Toothpaste

such as sodium stearate and the closely related potassium stearate.

Today, soaps are made from fats and oils that react with lye (sodium hydroxide).

Solid fats like coconut oil, palm oil, tallow (rendered beef fat), or lard (rendered pork fat), are used to form bars of soap that stay hard and resist dissolving in the water left in the soap dish.

Oils such as olive oil, soybean oil, or canola oil make softer soaps.

Castile soap is any soap that is made primarily of olive oil.

This type of soap is known for being mild and soft.

As warm liquid fats react with lye and begin to saponify, they thicken like pudding.

At this point dyes and perfumes are often added.

The hardening liquid is then poured into molds, where it continues to react by generating heat.

After a day, the bars can be cut and wrapped, but the saponification process continues for a few weeks, until all of the lye has reacted with the oils.

Soaps are often "superfatted," so after all of the lye has reacted with the fats, there are still fats left over.

This is impor- tant for two reasons.

First, the resulting soap is easier to cut and feels smoother on the skin.

Second, the extra fats ensure that all of the lye reacts, so no lye is left to irritate the skin.

The saponification process results in about 75 percent soap

and 25 percent glycerin. In homemade soaps, the glycerin is left in, as it acts as an emollient (skin softener) and creates a nice feel. In commercial soaps, the glycerin is often removed and sold separately, sometimes showing up in skin moisturizers that rem- edy soap's skin-drying effects.

Commercial bar soaps contain sodium tallowate, sodium

cocoate, sodium palmate, and similar ingredients, all of which are the results of reacting solid fats-tallow, coconut oil, and palm kernel oil, respectively-with lye.

To these ingredients, they add fatty acids such as coconut

acid and palm acid (the fats in coconut oil and palm kernel oil).

Surfactants

209 These extra fats ensure that the lye is completely reacted and that the soap has a good feel.

Polyethylene glycols such as PEG-6 methyl ether may be

added as either surfactants, detergents, emulsifiers (to make the dyes and perfumes blend evenly), or thickeners. Glycerin is added as an emollient and texture enhancer. Sor- bitol is another emollient that is often used along with glycerin because it makes the soap more transparent. Titanium dioxide is added to make the soap opaque.

Pentasodium pentetate, tetrasodium etidronate, and tetra-

sodium EDTA are added as water softeners and to protect the dyes and perfumes from the effects of metal ions in the mixtures.

These compounds lock up calcium and magnesium in the water,

preventing them from reacting with the soap to form insoluble soap scum.

Detergent Bars

Not all bars that lather contain just soap. Many feature the same detergents that you find in shampoo as well. In addition to the soaps and fatty acids, some bars contain cocamidopropyl betaine, a mild amphoteric detergent that is added to control irritation without decreasing suds or cleaning power, and benzine sulfonate detergents such as sodium dode- cylbenzinesulfonate. Other detergents, such as sodium isethion- ate and sodium cocoyl isethionate, are also common.

Preservatives

BHT (butylated hydroxytoluene) is sometimes added as an

antioxidant preservative to keep the oils from going rancid.

Antimicrobials

Antibacterial soaps usually contain triclosan or triclocarban as the active antibacterial ingredient.

Why There's Antifreeze in Your Toothpaste

Sodium Dodecylbenzenesulfonale

Chemical Formula

Synonyms

Sodium 4-dodecylbenzenesulfonate

Description

White or light yellow flakes. Sodium dodecylbenzenesulfonate is a straight-chain benzene sul- fonate, a type of detergent.

Uses

Straight-chain benzene sulfonates were invented as replacements for branched-chain benzene sulfonates, which were the first detergents but which could not be easily broken down by microbes in streams, rivers, or sewage treatment plants. These detergents are in use in many products, from laundry deter- gents to detergent soap bars. They are the most common type of detergent in use.

Surfactants

Sodium Isethionate

Chemical Formula

OH

Na+ -0-8=0

IIo

Synonyms

Sodium 2-hydroxyethanesulphonate • sodium cocoyl isethionate

Description

White solid or flakes.

Uses

Sodium isethionate is an amphoteric detergent used in detergent bar soaps. It makes a dense lather in addition to the lather made by the soap. It is nondrying and mild on the skin. It works equally well in soft or hard water. It is also an antistatic agent in shampoos. Sodium cocayl isethionate is a related amphoteric detergent used in mild bath soaps, toothpastes, and baby soaps.

Focus: Detergents

.,. r ~~ -~ No matter how much fun it is to squish our toes in the mud, most people love to be clean. We want our clothes to be fresh, our dishes to be spotless, and our cars to be shiny. We continue to invent new ways to make things clean.

Detergents

Detergents have molecules with one side that prefers water

(hydrophilic), and another side that prefers oils and fats

Why There's Antifreeze in Your Toothpaste

(hydrophobic). The hydrophilic side attaches to water molecules, and the hydrophobic side attaches to oil molecules. This action allows the oil droplets to break up into smaller droplets sur- rounded by water. These smaller droplets, no longer stuck to the material to be cleaned, are washed away.

Surfactants

Detergents and soaps are surfactants, which is short for "sur- face-active agent."

Surfactants have a hydrophilic side of the molecule that

attaches to water, and a hydrophobic side of the molecule that avoids water. In the absence of oils, the hydrophobic side sticks out of the surface of the water drop. There is no longer any water at the surface to form a strong surface tension, so the water no longer beads up, but spreads. The hydrophobic end of the mole- cule is also free to attach to grease, fat, or oil on the surface, which aids in the spreading.

Emulsifiers

Some detergents and surfactants are used as emulsifying

agents. An emulsifier keeps oil droplets and water droplets from joining together, so a thick mixture of oil and water will not sepa- rate. Examples of emulsions are mayonnaise, butter, cream, homogenized milk, and salad dressings.

Soap

Beef fat reacting to alkaline wood ashes led to the creation of the earliest soap, and it has been the cleaning product of choice for millennia. Soap is made from a fatty acid that is reacted with an alkali. The acid end of the fatty acid reacts with the alkali to form a salt that is water soluble. The other end is the fatty end, which repels water and is attracted to fats and oils. The process of making soap is called saponification.

Types of Detergents

German scientists created the first detergents during the short- ages of World War II. These were called branched-chain alkyl

Surfactants

213 benzene sulfonates. Like soap, they could take hard minerals out of water, leaving it soft. As with soap, the minerals formed a scum, familiar to anyone who has seen a bathtub ring.

Microbes could not break down branch-chain detergents, so

they left foam in river water. They were replaced by straight-chain alkyl benzene sulfonates, such as sodium dodecylbenzene- sulfonate and sodium xylenesulfonate. Straight-chain detergents don't work in hard water. Phos- phates were added to detergents to soften the water, but phos- phates are excellent fertilizer for algae in rivers and oceans. The algae blooms deplete the oxygen in the water, which in turn kills fish. Phosphates were replaced with other water softeners such as sodium carbonate and EDTA. Later, surface-acting polyglucosides were created. These sugar-based detergents are easily broken down by microbes, leaving no traces in the environment. They consist of a pair of glucose molecules, with hydrocarbon side chains attached to act as the hydrophobic ends. They are milder than soaps, and they work in hard water. Another type of detergent is a group called the pyrrolidones.

These are complex molecules that dissolve in both water and

organic solvents.

Additives

Some laundry detergents contain "optical brighteners." These are fluorescent dyes that glow blue-white in ultraviolet light. The blue-white color makes yellowed fabrics appear white.

Laundry detergent may also contain polyethylene glycol, a

polymer that prevents dirt from redepositing on the clothes. This function used to be the job of phosphates. Another polymer used for this purpose is carboxy methyl cellulose, which is derived from natural cellulose but is very soluble in water.

Yet another ingredient in laundry detergents is diethyl ester

dimethyl ammonium chloride (DEEDMAC). It is a fabric softener. It is a cationic surfactant that is rapidly biodegradable. It works by reducing the friction between fibers, and between fibers and

Why There's Antifreeze in Your Toothpaste

the skin. Cationic surfactants are those where the hydrophilic part (in this case the ammonium chloride) is positively charged, and is attracted to substrates that are negatively charged, such as proteins and many synthetic fabrics. Hair conditioners use this trick also. You can think of hair conditioner as fabric softener for your head.

A cationic surfactant will often have an ammonium group

attached to a halogen, as in the ammonium chloride mentioned above. Anionic surfactants, such as soap, often have a sodium, potassium, or ammonium group, as in sodium stearate.

Nonionic surfactants like polyethylene glycol esters (PEG)

are used as mild cleansers, or to add viscosity to mixtures such as shampoo. Amphoteric surfactants are those that are an acid and a base at the same time (like water is). Cocamidopropyl betaine, for example, is used in shampoos to stabilize foam and thicken the mixture.

Some examples of detergents and surfactants are

• ammonium lauryl sulfate • lauryl glucoside

Classes of detergents

• Alkyl benzene sulfonates (ASS). Branched-chain anionic sur- factants. Slow to biodegrade. Seldom used. • Linear alkyl benzene sulfonates (LAS). Straight-chain anionic surfactants. Somewhat slow to biodegrade. Most common surfactants in use. • Alkyl phenoxy polyethoxy ethanols (alcohol ethoxylates). Also called nonyl phenoxy ethoxylate, or nonyl phenol. Slow to biodegrade. Nonionic surfactant. Used in dry detergents. • Diethanolamine and triethanolamine. Commonly used to neu- tralize acids in shampoos, to reduce irritation (pH-balanced shampoos). Slow to biodegrade.

Surfactants

215 • Alkyl ammonium chloride (quaternium-15). Acts as a surfac- tant, disinfectant, and deodorant. • Alkyl glycosides. Quick to biodegrade. Made from oils and sugar.

Detergent additives

• Mono ethanol amine (MEA). A solvent used to dissolve other laundry detergent ingredients. It also lowers the freezing point of liquid laundry products to allow them to be trans- ported in cold weather. • Sodium carbonate peroxide. Used as a bleach. It breaks down into sodium carbonate and hydrogen peroxide, which does the actual bleaching. • Sodium sulfate. Used to dilute powdered detergents.

XylenesuIfonates

See entry, page 138.

Foam Stabilizers

19 Foams are formed when surfactants mix with air instead of with oils or fats, and adding one of those substances generally makes the foams break down. For instance, beating egg whites into a foam is much harder to do if grease or oil is added to the egg white mixture. Like- wise, if you want a thick lather on your hair, you will have to use more shampoo than is needed to remove the dirt and oil. Since we want the texture of products like shaving cream to stay stable, and since shampoo advertisers like to pretend that unneces- sary extra lather is an important selling point, foam stabilizers are helpful in preventing foams from breaking down.

Cocamide MEA

Cocamide DEA

Cocamide TEA

Chemical Formula

II

HI~OH

N(

OH

Cocamide DEA

Why There's Antifreeze in Your Toothpaste

Synonyms

Coconut

fatty acid monoethanolamide • coconut fatty acid diethanolamide· coconut fatty acid triethanolamide • N-coco alkyl derivatives

Description

Viscous clear to amber liquid, or solid flakes. These ingredients are made from fatty acids in coconut oils, reacted with diethanolamine, or its mono- or triethanolamine relatives.

HO~N~OH

Diethanolamine

Uses

Cocamide ethanolamines are used as foaming agents in shampoos

and bath products and as emulsifying agents in cosmetics.

Tetrasodium Pyrophosphate

See entry, page 46.

Conditioners

20 Conditioners are surfactants that neutralize the electrical charge on the surface of the hair, and smooth down protein scales on the hair shafts. These effects make the hair easier to style and less prone to static electricity. Conditioners can be made from oily surfactants or fatty surfac- tants, or a mixture of both. The more solid fatty conditioners can glue together split ends and damaged hair. The more liquid oily condi- tioners smooth the hair and then rinse out more effectively.

Cetyl Alcohol

See entry, page 57.

Cetrimonium Chloride

Chemical Formula

Why There's Antifreeze in Your Toothpaste

Synonyms

I-hexadecanaminium • cetyltrimethylammonium chloride· C16-

alkyltrimethylammonium chloride

Description

Clear liquid.

Uses

Cetrimonium chloride is used in hair conditioners, fabric softeners, and antistatic agents for hair and fibers. It makes fabrics and hair less prone to static electricity buildup by making them slightly conductive.

Silicones

Chemical Formula

0"-... 1.)0","",- 1./0"-... 1.10 81, 81 81 ,

, ,n ..................................•................

Dimethicone

Conditioners

1./0-1 I./oll I./o( I. -81 : 81

,81 : 81-

: j I : I , , ,m .......................

Cetyl dimethicone

Synonyms

Polydimethylsiloxane (PDMS) • dimethicone· cyclomethicone· cetyl dimethicone • cyclopentasiloxane • silicone oil

Description

Slippery liquid. Silicones are a large group of compounds that include large poly- mers containing silicon. Depending on the formula and the degree of polymerization and cross-linking of the polymers, they may be slip- pery liquids, waxes, or rubbers.

Why There's Antifreeze in Your Toothpaste

Uses

Silicones are used as emollients (skin softeners), as lubricants, as thick- eners, and as volatile liquids that make coatings feel smooth but evap- orate without leaving a greasy residue. Highly cross-linked silicone films are used in cosmetics to form coatings that absorb sebum (skin oils) and prevent shine. Cyclopentasiloxane is a low-viscosity, volatile liquid that is used as a carrier. It lubricates, and prevents hairsprays from being sticky to the touch. It evaporates completely, leaving no residue.

Dimethicone is another name for polydimethylsiloxane and is

used to impart a soft velvety feel to hair or skin products. It is also used as an emulsifier for water-in-oil emulsions. Trimethylsiloxysilicate is a film-forming resin that is used to keep hand lotions and sunscreens from washing off. Cetearyl methicone is a polysiloxane wax. It replaces petrolatum in such products as hand lotions to give them a nongreasy feel.

Panthenol

See entry, page 126.

Propellants

21 Propellants are gases or liquids that quickly expand into gases to carry a substance (often a glue, as in the case of hairspray, but sometimes a foam, as in whipped cream) out of its container.

Nitrous Oxide

Chemical Formula

N20

N=N=O

N-O

Bonds resonate between single/triple and double

Synonyms

Dinitrogen oxide'dinitrogen monoxide

Description

Colorless, nonflammable gas with a sweet odor.

Uses

Nitrous oxide is used as a foaming agent and propellant in whipped cream. It dissolves easily in fats under pressure, and comes out of solu- 223

Why There's Antifreeze in Your Toothpaste

tion when the pressure is reduced, much like the carbon dioxide in a can of soda. Nitrous oxide dissolves in the fats that sheath the nerve cells, and produces numbing and mild intoxication. It is the "laughing gas" den- tists use to make patients less aware of pain. Many gases dissolve in fats and make good propellants. However, most are flammable or toxic, or they react with the fats. Other possi- ble propellants, such as the propane used in hairsprays or in Freon, also cause intoxication when they dissolve in the fats around nerve cells. These substances are not used, since their flammability, safety, cost, or taste makes them less desirable than nitrous oxide for spray cans of whipping cream.

Isobutane

Chemical Formula

C4HlO

Synonyms

Butane

Description

Colorless, odorless gas.

Uses

Isobutane is used in cigarette lighters and camp stoves as a fuel. It is easily liquefied under pressure, and the liquid becomes a gas imme- diately when the pressure is released. It is also used as a propellant in hairsprays and spray breath fresheners.

Propellants

225 ~ Chemistry Lesson Isobutane is a compound in a class of chemicals called alkanes. Al- kanes are chains of carbon atoms where each carbon atom has as many hydrogen atoms attached as possible. This means that all of the bonds between carbon atoms are single bonds (no double bonds). Such a molecule is said to be saturated. The simplest alkane has only one carbon atom. It is called

methane

H-C-H

Methane, CH,

It appears here with all of the hydrogens showing. In pictures of the structural formulas in organic chemistry, carbon atoms and hydrogen atoms typically aren't shown because the picture would just be too crowded. A carbon atom is implied whenever a line ends or whenever one line joins another. Hydrogens are assumed to connect to any carbon that has a free bond. (Carbon can form four bonds, so if only three are showing, the other is attached to a hydrogen.)

Ethane, C,H,

Using this convention, ethane is just a line. There is a carbon at each end, and each carbon has three bonds left, so there are six hydro- gens in the molecule.

Propane, C,H,

Why There's Antifreeze in Your Toothpaste

Propane is a bent line. There is a carbon at each end, and one in the middle, at the bend. Each carbon at an end has three bonds, and the carbon in the middle has only two bonds left, so we have eight hydrogens in the molecule.

Butane, C,H,o

Butane has four carbons. With four carbons, we suddenly have two different ways the carbons can link up. They can be all in a row, like the molecule shown above, or one carbon can be in the middle, bonding to three carbons and a hydrogen.

Isobulane, C,H lO

An alkane with all the carbons in a row is called butane, and the form with one carbon in the middle is known as isobutane. The iso is short for isomer, which means a molecule that has the same atoms arranged in a different way.

Penlane, CsH"

When there are five carbons, there are three different ways to arrange them. A pentane is an alkane molecule where the carbons are all in a row. 2-melhylbulane, CsH"

Propellants

227 When molecules start to get complicated like this, they must be named carefully, according to some rules.

One rule is to look for the longest unbranched alkane in the molecule.

In this molecule, it is butane (four carbons).

Next, describe the branch.

In this case, it is methane (one carbon).

Then describe where the branch is attached.

In this case, it is attached to the second carbon in butane.

The name is thus 2-methylbutane. + 2,2-dimelhylpropane, CsH" The other way five carbon atoms can be arranged in an alkane is to attach two of them to the middle carbon atom in propane.

The molecule above has two methanes and a propane, and both methanes are attached to the second carbon in the propane.

Thus it is called 2,2- dimethylpropane.

Up until pentane, all of these alkanes were gases.

Pentane is a liq- uid.

The longer the chain of carbons gets, the harder it is for one of the molecules to escape into the air.

Hexane, C6H14

Hexane is next. There are many ways to put six carbons together; there are only two forms shown here. The first is simply the carbons all in a row. o

Cyclohexane, C6H"

Another way to put six carbons together is to attach them in a ring. The result is not the same as hexane, because the two hydrogens

Why There's Antifreeze in Your Toothpaste

at the end of hexane are missing. The ring form is called cyclohexane. While three carbons could have formed a three-sided ring, the bonds would be very strained, and the molecule would be unstable. Like- wise, four and five carbon rings can form, but they are also less sta- ble, and break down into the other forms. But with six carbons, the molecule is quite stable and stays in a ring easily.

Heptane

The simple chain made of seven carbons is called heptane.

Octane

When eight carbons occur in a chain, it is called octane. A mix- ture of liquid alkanes we call gasoline burns in our automobiles. If the mixture has a lot of lightweight molecules that evaporate easily, it can ignite too readily in the engine, causing premature ignition, or "knocks and pings." If the gasoline has more of the longer molecules, it burns more slowly, and only ignites when the spark plug fires. These gasolines are called high-octane fuels. Alkanes keep going up in size. When they get up to C1sH,s they become solids. The familiar white solid paraffin, which is commonly used for making candles, is made up of solid alkanes. Paraffin is not really a wax, as waxes are made up of more complicated molecules.

Dimethyl Ether

Chemical Formula

Propellants

Synonyms

1,2-dimethoxyethane

Description

Colorless, flammable gas with an odor of ether.

Uses

Dimethyl ether is used as a propellant in aerosols. It is also a solvent, a fuel used in welding, and a refrigerant. In high concentrations, it has an anesthetic effect.

Polymers and Glues 22

Glues are often polymers, long-chained molecules that bind things together either by reacting with them or by trapping them in a tangle.

Vinyl Acetate

Chemical Formula

o )=0 o )=0 o )=0

Synonyms

Poly(vinyl acetate) • PYA • vinyl acetate/crotonates/vinyl neode- canoate copolymer

Description

White powder. 231

Why There's Antifreeze in Your Toothpaste

Uses

Polyvinyl acetate is an ingredient in white glue. It is a copolymer with vinyl alcohol in latex paints. o )=0

OH

o )=0

OH

Copolymer of vinyl acetate and vinyl alcohol

This molecule is a copolymer with polymethyl methacrylate

(PMMA) in acrylic latex paints, where the hydrophobic PMMA is sur- rounded by hydrophilic polyvinyl acetate molecules. Such a suspen- sion of a hydrophobic polymer wrapped in a hydrophilic polymer is called a latex. A copolymer is a polymer made up of two or more different building blocks, called monomers. ~ Chemistry Lesson Many common plastics are made from simple building blocks called vinyl monomers. These are little molecules that contain carbon dou-

ble bonds. The simplest one is ethylene

" / c=c / "-

Polymers and Glues

233 Ethylene molecules can join together into immensely long chains, converting the double bond into a single bond as they join to become polyethylene.

When

the propylene molecule polymerizes, the result

IS

polypropylene. When the vinyl chloride molecule polymerizes, polyvinylchloride (PVC) is the result.

CI

When the styrene molecule polymerizes, the result is poly-

styrene-Styrofoam. When the methyl methacrylate molecule polymerizes, it is poly- methyl methacrylate-Plexiglas.

Why There's Antifreeze in Your Toothpaste

'::::-o o

'::::-o

When the tetrafluoroethylene molecule polymerizes, it's poly-

tetrafluoroethylene, more commonly known as Teflon.

Focus: Hairspray

$ It's just a simple little spray can with a simple task-to ~ keep hair in place. So why does it contain so many dif- ~ ferent ingredients?

Hairspray is formulated to hold hair in place and keep

it shiny, without flaking off, without failing, even in humid conditions. Yet it must retain the ability to be washed out of the hair easily for at least forty-eight hours, and it must not clog the spray can's nozzle. Complex polymers are needed to perform all of these tasks well. The basic building blocks of these polymers are the same ones found in acrylic paints and white glue. But they are put together in a different way.

The two main polymers used in hairspray are vinyl

acetate/crotonates/vinyl neodecanoate copolymer (a form of vinyl acetate) and octylacrylamide/acrylates/butylaminoethyl

Polymers and Glues

235 methacrylate copolymer (a form of methacrylate). These poly- mers are carried in a base of water and alcohol (usually dena- tured), and the liquefied gas dimethyl ether, which acts as the propellant. The dimethyl ether boils away as a gas when the spray head is pushed down, propelling the rest of the ingredients out in a fine mist.

The emulsifier aminomethyl propanol serves several pur-

poses in hairspray. It acts as a buffering agent, controlling the acidity of the mixture to make it neutral ("pH balanced"). It also helps keep the polymers mixed with the water and alcohol, and controls the water solubility of the final mist, giving it the needed humidity resistance. It also helps to form the polymers into a gel.

Sodium benzoate is used as a preservative, although it also

functions as a corrosion inhibitor.

Cyclopentasiloxane is a volatile silicone used to make the

film water-repellent, and to eliminate tackiness. It is a thickener; it acts as a lubricant and gives the resulting coating a silkier feel.

Sodium PCA is a moisturizing agent; it draws moisture from

the air and holds it.

Some sprays include vitamins such as tocopherols (vitamin

E) or panthenol, which is metabolized in the skin to become pan- tothenic acid, a B vitamin. Since hair does not metabolize ("It's dead, Jim"), these sprays perform the functions of antioxidants (tocopherols). In other words, they add shine and moisture (pan- thenol) rather than perform their normal vitamin roles. Moisture helps prevent damage during combing.

Hydrolyzed soy proteins are also sometimes added to hair-

spray. These are more commonly known as soy sauce and MSG (monosodium glutamate), an amino acid.

Butylene glycol is sometimes used as a humectant (moistur-

izer) and preservative if the spray contains food items such as vitamins and proteins. It also helps products to retain their scents.

Why There's Antifreeze in Your Toothpaste

Vinyl Alcohol

Chemical Formula

OH

Synonyms

PYA

Description

White powder.

OH

Uses

Polyvinyl alcohol is a main ingredient in latex paints, hairsprays, shampoos, and glues. It forms polymers and copolymers with other monomers, such as vinyl acetate and methyl methacrylate When the polymers are cross linked using borax, you get the chil- dren's toy Slime.

Methacrylate

Chemical Formula

~o o

Polymers and Glues

Synonyms

Polymethyl methacrylate (PMMA) ·octylacrylamide/acrylates/butyl- aminoethyl methacrylate copolymer· Plexiglas

Description

Clear solid. Methacrylates and acrylates are a large group of polymers that together form acrylic plastics used in many common household products.

Uses

Acrylics are used in floor polish, hairsprays, latex paints, and glues as well as plastic items and packaging.

Silicones

See entry, page 220.

Abrasives and

Dental Additives 23

So what are all those things in my toothpaste? How can it polish, whiten, prevent cavities, prevent plaque, prevent gum disease, and freshen my breath all at the same time?

Hydrated Silica

Chemical Formula

Synonyms

Silicic acid· silica gel· amorphous silicon dioxide

Why There's Antifreeze in Your Toothpaste

Description

A transparent colloid (gel).

Uses

Hydrated silica is the abrasive used in gel toothpastes, or in the clear portion of striped toothpastes.

It is often used as a secondary abrasive in opaque toothpastes as well.

When dried in an oven, hydrated silica loses its water and becomes a desiccant (a substance that attracts water from the air).

You find little packets of silica gel crystals in containers whose contents would be damaged by condensing moisture, such as vitamin bottles, consumer electronics, pepperoni, or leather products.

Silica gel can be made by reacting an acid with sodium silicate, which is sold in drug stores as "water glass" or "egg keep," and is used to paint eggs to seal them from air and prevent spoilage.

Drying the resulting gel will get the desiccant, or it can be used wet in toothpastes.

You can find sodium silicate in the colorful Magic Rocks seen in gift shops at museums.

The dry form is mixed with salts of various metals.

When you drop them in water, the sodium is replaced by the metal.

The resulting metallic silicate is not soluble in water, and it takes on a color characteristic of the metal (e.g., copper is blue).

The metallic silicate is also a gel, so it expands and grows into colorful sta- lagmites in the water.

Focus: Toothpaste

fJ!Ii;d

The quality of toothpaste seems to improve every

day. We have anticavity toothpaste, extra-whitening

' •.

toothpaste, toothpaste with mouthwash, toothpaste for sensitive teeth, toothpaste with stripes, clear tooth- paste, and even liver-flavored toothpaste for dogs. Modern toothpaste has to do many things. It must have abra- sives to scour off bacterial films. It must have fluorides to harden the teeth against decay. It must have a strong enough pleasant

Abrasives and Dental Additives

241 flavor to hide the bad tastes of decaying bits of previous meals, as well as the awful taste of some of the other ingredients, such as detergents and phosphates.

Toothpaste must have thickeners to help it squeeze out of

the tube and stay on the toothbrush. It must have detergents to remove fatty films, water softeners to make the detergents work better, and sweeteners (preferably non-nutritive so as not encourage bacteria).

Toothpaste Ingredients

The most recognized toothpaste ingredient is probably the class of compounds known as fluorides. Stannous fluoride was the first to be used in toothpaste because, unlike sodium fluoride, it did not lose its effectiveness when combined with the abrasive most common at the time, calcium phosphate. Later, sodium mono- fluorophosphate came into popular use because it too could be used with the common abrasives.

When hydrated silica became the abrasive of choice, sodium

fluoride could be used, and it has become the most widely used fluoride in contemporary toothpaste. Hydrated silica is the transparent abrasive used in gel tooth- pastes and in the clear parts of striped toothpaste. It has come into common use in white opaque toothpastes as well, because of its compatibility with sodium fluoride.

Fluorides work better in combination with surfactants, which

help the remineralization process. The most common are the lauryl sulfates, such as sodium lauryl sulfate or ammonium lauryl sulfate.

Surfactants (detergents) also help clean the teeth; they pro-

vide a foam that helps to carry away debris. Moreover, lauryl sul- fates have significant antibacterial properties, and they can penetrate and dissolve plaque.

Lauryl sulfates can irritate oral membranes, and so a similar

detergent, lauryl sarcosinate, often replaces some or all of the lauryl sulfate. Allantoin is sometimes added to relieve irritation caused by detergents, alkalies, and acids.

Why There's Antifreeze in Your Toothpaste

The sequestering agent tetrasodium pyrophosphate (TSPP)

removes calcium and magnesium from the saliva, so they can't deposit on teeth as insoluble deposits called tartar (calcified plaque). In this respect it acts as a water-softening agent. How- ever, it won't remove tartar that already exists.

TSPP is slightly alkaline and has a bitter taste, requiring

additional flavorings to mask it. Also, additional detergents must be added to keep it in solution. All of these factors can irritate oral membranes and cause sensitivity.

Polymers such as the acrylic PVM/MA copolymer are added

to prevent bacteria from breaking down pyrophosphates. Other long polymers used are polyethylene glycol (PEG) in various weights (PEG-B, PEG-8, PEG-40, etc.), and polypropylene glycol

(PPG).

Sodium bicarbonate (baking soda) is added for taste and

"mouth feeL" It combines with acids to release carbon dioxide gas, adding to the foam produced by brushing. It is a mild abra- sive. It may reduce the numbers of acid-loving bacteria in the mouth, although this effect lasts only as long as the mouth stays alkaline.

Sodium carbonate peroxide is added to "peroxide" toothpaste

as a whitener. It breaks down into sodium carbonate (washing soda) and hydrogen peroxide. The hydrogen peroxide bleaches the teeth and kills germs. Sweeteners such as sodium saccharin are added for taste. Other flavors are usually strong essential oils in the mint family. The antibacterial agent triclosan is added to kill plaque-form- ing microbes. Various types of gum are used to thicken the paste. They also help retain moisture, so the toothpaste does not dry out if the top is not replaced. Titanium dioxide is used to make pastes opaque and white.

Abrasives and Dental Additives

Stannous Fluoride

Chemical Formula

SnF2

Synonyms

Tin fluoride

Description

White crystals.

Uses

Stannous fluoride is used in toothpastes and dental rinses to protect tooth enamel from attack by bacteria-cavities (also known as den- tal caries). It was the first fluoride used for that purpose, in the tooth- paste Crest. The active part of the molecule is the fluoride ion, which is why two other fluorine-containing compounds, sodium fluoride and sodium monofluorophosphate, are also used. Stannous fluoride can be used with abrasives that contain cal- cium, which prevents sodium fluoride from being effective. Sodium monofluorophosphate was developed to avoid infringing on the Crest patent. Fluorides work in two ways. They reduce the ability of bacteria to make acids, and they remineralize the areas of the tooth that have been attacked by acids from bacteria.

Sodium Fluoride

Chemical Formula

NaF

Description

White crystals.

Why There's Antifreeze in Your Toothpaste

Uses

Sodium fluoride is used in toothpastes and dental rinses to protect tooth enamel from attack by bacteria-cavities (also known as den- tal caries). The active part of the molecule is the fluoride ion, which is why two other fluorine-containing compounds, stannous fluoride (tin fluoride) and sodium monofluorophosphate, are also used. Fluorides work in two ways. They reduce the ability of bacteria to make acids, and they remineralize the areas of the tooth that have been attacked by acids from bacteria.

Sodium Monofluorophosphate

Chemical Formula

Na2P03F

Synonyms

MFP

Description

White crystals.

Uses

Sodium monofluorophosphate is used in toothpastes to protect tooth enamel from attack by bacteria-eavities (also known as dental caries). It was developed to avoid infringing on the Crest patent for stannous fluoride. The active part of the molecule is the fluoride ion, which is why two other fluorine-containing compounds, sodium fluoride and stan- nous fluoride, are also used.

Like stannous fluoride, sodium monofluorophosphate can be

used with abrasives that contain calcium, which prevents sodium fluo- ride from being effective. Fluorides work in two ways. They reduce the ability of bacteria to make acids, and they remineralize the areas of the tooth that have been attacked by acids from bacteria.

Index

1,2-dimethoxyethane. See dimethyl ether 1,2,3 trihydroxy propane. See glycerin 1,2,3,4,5,6-hexanehexol. See mannitol 1,3-benzenediol. See resorcinol 1,3-bis(hydroxymethyl)-5,5- dimethylimidazolidine-2,4- dione. See DMDM hydantoin

I,3-dichloro-1 ,3,5-triazine-

2,4,6( 1H,3H,5H)-trione sodium salt.

See sodium dichloroisocya- nurate 1,7,7-trimethylbicyclo[2.2.1] -2-hep- tanone.

See camphor I-heptadecanecarboxylic acid.

See stearic acid I-hexadecanaminium.

See cetrimonium chloride I-hexadecanol.

See cetyl alcohol I-hydroxyethanecarboxylic acid.

See lactic acid I-octadecanol.

See stearyl alcohol 2,2-dimethylpropane,227 2,3-dihydroxybutanedioic acid.

See tar- taric acid 2,4,4'-trichloro-2'-hydroxydiphenyl ether.

See triclosan 2,6-di-tert-butyl-4-methylphenol.

See butylated hydroxytoluene 2-acetoxybenzoic acid.

See acetylsali- cylic acid 2-amino-2-methyl-l-propanol.

See aminomethyl propanol 2-bromo-2-nitropropane-I,3-diol, 43-44,203 2-butenedioic acid.

See fumaric acid 2-camphanone.

See camphor 2-ethylhexyl salicylate, 9 2-hydroxy-I ,2,3-propanetricarboxylic acid.

See citric acid 2-hydroxybenzoic acid.

See salicylic acid 2-hydroxypropanoic acid.

See lactic acid 2-isopropyl-5-methyl-cyclohexanol.

See menthol 2-methyl-4-isothiazolin-3-one (MI).

See isothiazolinone

Index

2-methylbutane,227 2-tert-butyl-4-hydroxyanisole. See butylated hydroxyanisole 3,7-dihydro-3,7-dimethyl-1 H- purine-2,6-dione. See theo- bromine 3-carbomethoxypyridine. See methyl nicotinate 3-ethoxy-4-hydroxybenzaldehyde. See ethyl vanillin 3-hydroxyphenol. See resorcinol 3-methoxy-4-hydroxybenzaldehyde.

See methyl vanillin

3-pyridinecarboxylic acid. See methyl nicotinate 3-tert-butyl-4-hydroxyanisole. See butylated hydroxyanisole 4-aminobenzoic acid. See para-amino benzoic acid 4-isopropylbenzyl salicylate, 10 4-0-a-D-glucopyranosyl-D-glucitol.

See maltitol

5-chloro-(2,4-dichlorophenoxy)phenol.

See triclosan

5-chloro-2-methyl-4-isothiazolin-3-one (Mel). See isothiazolinone 6-hydroxy-5- (2-methoxy-5-methyl-4- sulfophenylazo)-2-naphtalene- sulfonic acid sodium salt. See allura red 7-D-glucopyranosyl-3,5,6,8-tetrahy- droxy-1-methyl-9.10-dioxoan- thracene-2-carboxylic acid. See carmine 8-methyl-N-vanillyl-6-nonenamide. See capsaicin a-amylase, 35-36 l3-carotene. See beta-carotene

abrasives, 169, 239-244 absorbers, 11

Acacia senegal, 149

Acacia seyal, 149

acesulfame K. See acesulfame potassium acesulfame potassium, 33, 77, 80 acetaminophen, 182-183 acetic acid, 27, 97,114,147,167. See also vinegars acetylsalicylic acid, 167, 181-182. See also aspirin acids, 1,5,13,15-16,20-22,27,29,31, 40,47,49-51,63-68,76,80,90, 97,110,115,123,143,146-147, 154,155,165-167,169,181-182, 185-186,193,201-204,208,235, 241,243 acne medications, 164-166, 167, 168, 187 acrylates,237 acrylics, 237 adenosine, 158 adrenaline, 160. See also epinephrine Advil. See ibuprofen aerosols, 229 aftershave lotions, 60 agar, 139-140 agaropectin, 139 agarose, 139-140 alanine, 123 alcohol ethoxylates. See alkyl phenoxy polyethoxy ethanols alcoholic beverages, 55-56 alcohols, 3, 55-60,127,146,153,165, 172-173, 174. See also ethanol denatured, 56, 70,174,235 sugar, 33-34, 83-88,96

Aleve. See naproxen alginates, 142-143 alizarin, 112 alkalies, 114, 185, 193-194, 196, 197, 207,212,241 alkaline solutions, Ill, 196,203 alkaloids, 79, 178 alkanes, 225-228 alkyl ammonium chloride, 215 alkyl benzene sulfonates (ABS), 214 alkyl glycosides, 205, 215 alkyl phenoxy polyethoxy ethanols, 214 allantoin, 185, 241 allomaleic acid. See fumaric acid allura red, 113, 118-20. See also FD&C

Red #40

alpha hydroxy acid, 165 alpha-hydroxycaprylic acid, 165 alpha-hydroxyethanoic acid, 166 alpha-hydroxyoctanoic acid, 166 alpha-hydroxypropionic acid. See lactic acid alpha-oxodiphenylmethane. See benzophenone alpha-oxoditane. See benzophenone aluminum calcium silicate, 29 aluminum hydroxide, 114

Alzheimer's disease, 184

amides,173 amine groups, 178 amino-2-methylpropanol. See aminomethyl propanol amino acids, 72, 201-202, 204, 235 aminomethyl propanol, 45-46, 235 ammonia, 200 ammonium chloride, 202, 214 ammonium glycolate, 165 ammonium laureth sulfate, 200-201

InJex

247 ammonium lauryl ether sulfate.

See ammonium laureth sulfate ammonium lauryl sulfate, 199-200, 201,214,241 ammonium persulfate, 155 ammonium sulfate (yeast nutrient), 155 ammonium xylenesulfonate, 202.

See also xylenesulfonates amorphous silicon dioxide.

See hydrated silica AMP.

See aminomethyl propanol, cyclic aminomethyl propanol AMP-95.

See aminomethyl propanol amphetamines, 160 amyl p-methoxy cinnamate, 5 amylase, 87,155 amylopectin, 144-145 amylose, 31-32,144-145,152 analgesics.

See pain relievers anesthesin.

See benzocaine anesthetics, 60, 172-175, 229 annatto, 105-106, 107, 114, 117 antacids, 169 anthocyanins,109-111 antibacterials, 13,25,26,42,67,86, 164-165,192,195,196,202-203, 241-242, 243, 244.

See also antimicrobials antibiotics, 36, 170,202,206 anticaking, 29 anticoagulants, 19, 184 antifreeze, 22, 43, 58, 70 antifungals.

See fungicides anti-inflammatories, 164, 182, 183, 184 anti-irritants, 60 antimicrobials, 21-44, 80,197,209.

Index

antioxidants, 14-21,64,67,80,94,95, 105-106,107,117,209,235 antipyretics. See fever reducers antiseptics, 18, 168 antistatic agents, 201, 204, 206,211,219 appetite depressants, 160 apples, 109 arabinogalactan oligosaccharides, 149 arginine, 123 arthritis, 184, 189 artificial smoke machines, 43 ascorbic acid, I, 15,40, 80, ISS. See also erythorbic acid ascorbyl palmitate, 15,21 aspartame, 33, 75, 76, 77-78, 79,81 aspartic acid, 76, 123 aspirin, 146, 158, 160-161, 167, 182-183, 184, 186. See also acetylsalicylic acid astringents, 64 atropine, 178 avobenzone, 9 azo groups, 120 azodicarbonamide, 155

b-bromo-b-nitrotrimethyIeneglycol.

See 2-bromo-2-nitropropane-I,3- diol bacteria, 36,121,136,137,139,241 bactrinol-IOO.

See 2-bromo-2-nitro- propane-I,3-diol baked goods, 23, 35, 77, 81,115,130, 133,148,152 baking powders, 47, 68 baking soda.

See sodium bicarbonate bath products, 3 beers, liS, 143 beeswax.

See esters belladonna alkaloids, 178 Benefat.

See Salatrim benzenecarboxylic acid.

See benzoic acid benzine ring, 8-9 benzine sulfonates, 201,209 benzoate of soda.

See sodium benzoate benzoates, 35 benzocaine, 70,171-174 benzoic acid, 21, 22 benzophenone, 2-5, 8, II benzophenone-3.

See oxybenzone benzoylbenzene.Seebenzophenone benzoyl peroxide, 153, 163-165, 167, 195 benzyl ester, 188 benzyl groups, 174 benzyl nicotinate.

See methyl nicotinate beta-carotene, 6, 105, 107, 109, 113-114, 117, 192 beta-gentiobiose crocetin.

See saffron beta hydroxyl acid, 165 betula oil.

See methyl salicylate BHA.

See butylated hydroxyanisole BHT.

See butylated hydroxytoluene bicarbonate of soda.

See sodium bicar- bonate bicarbonates, 64 biocides, 39, 203 birch sugar.

See xylitol bitrex.

See denatonium benzoate

Blxa orellana, 106

bixin, 106 bixin carotenoids See annatto bleaches, 163-164, 191-198,215 chlorine, 191-193, See sodium hypochlorite

hair, 168, 194 household, 191-194, 198 oxidizing, 192-193, 195 oxygen, 193-194 reducing, 13, 193 blue jeans, 121 blueberries, 1,37,109 boletic acid.

See fumaric acid bone extract.

See gelatin borax, 193, 196,236 boron, 196 botulism, 40, 41 bound glutamates, 73 branched-chain alkyl benzene sul- fonates,212-214 branched-chain benzene sulfonates, 210 breads, 27, 67, 148, 151, 152-155, 169 breath mints, 86 broccoli, 167 bromated flour.

See potassium bromate bromic acid.

See potassium bromate brominated vegetable oil, 80,148-149 bromine, 149 bronchial stimulators, 160 bronchodilators,40 buffering agents, 19,45-47,67,169, 196,203,235 bupivacaine, 173, 175 bursitis, 184 butane, 226-227.

Index

249 c

C16-alkyltrimethylammonium

chloride. See cetrimonium chloride caffeine, 79-80,157-158,159,160 cake mixes, 130 calcium, 46-47, 49-50,52,53, 100, 142, 143,148,154,201,209,242,243, 244 calcium caseinate, 123. See also caseinates calcium chloride, 193 calcium dioxide, 155 calcium EDTA. See ethylene diamine tetra acetic acid calcium hydroxide, 151, 193, 195 calcium hypochlorite, 192, 193-194, 195 calcium iodate, 155 calcium phosphate, 29, 241 calcium propanoate. See calcium propionate calcium propionate, 34-35, 67,155 calcium salt, 151 calcium sorbate, 23 calcium stearoyllactylate, 151. See sodium stearoyllactylate calcium sulfate, 155 camp stoves, 224 camphor, 187 candies, 60, 77,86,87,120,150,186 candles, 71 capsaicin, 188-189 capsicum oleoresin. See capsaicin caramel color, 80, 114-115 carbamide peroxide, 194 carbohydrates, 97,144 poorly absorbed, 83-88

Index

carbon dioxide gas, 68, 134, 153, 169, 224,242 carbonated water. See carbonic acid carbonic acid, 80 carboxy methyl cellulose, 213 carboxybenzene. See benzoic acid carboxyethyl groups, 146 carboxyl groups, 7-8, 65 (( (carboxymethyl)imino)bis(ethyleneni- trilo))tetraacetic acid. See diethylene triamine pentaacetic acid carboxymethyl groups, 146 carboxymethylcellulose. See methylcel- lulose, sodium carboxymethyl- cellulose carboxypropyl groups, 146 carcinogens, 156 carmine, 111-112, 114 carnauba wax. See esters carob bean gum. See locust bean gum carotenoids, 96, 97, 117 carrageenan, 100, 134, 139, 143, 147-148 casein, 123 casein proteins, 124 caseinates, 122-124 castile soap, 208 catalase, 169 cellulose, 32,98, 102, 138, 213

Ceratonia siliqua, 102

cereals, 77, 145 cetearyl methicone, 222 cetrimonium chloride, 204, 219-220 cetyl alcohol, 57, 203 cetyl dimethicone. See silicones cetyl palmitate. See esters cetylacetic acid. See stearic acid cetyltrimethylammonium chloride. See cetrimonium chloride CH-3565. See triclosan charcoal, 171 cheese, 23, 24,47, 72,82,106,107 chelating agents, 49-54. See also seques- tering agents chewing gum, 60, 77 chile saltpeter. See sodium nitrate chlorine atoms, 81 chlorine gas, 191-192, 193, 195 chlorine tablets. See calcium hypochlorite

Chlorogalum porneridlanum, 207

chloroprocaine, 175 chocolate, 125, 157, 158, 159 choline, 1, 20 chromophores, 192-193 cigarette lighters, 224 cigarettes, 60 cinnamates, 10 cinoxate, 10 citrates, 19, 100 citric acid, 13, 63-64, 66, 80, 90, 114, 165,203 cleaning products, 27

Clostridium botulinum, 40

coal tar, 120

Coca Cola, 157, 174

cocaine, 70,157,174 cocamide DEA. See cocamide

MEA

cocamide MEA, 201, 217-218 cocamide TEA, See cocamide MEA cocamidopropyl betaine, 201-202, 205-206,209,214

Coccus cacti, 111-112

cochineal extract. See carmine

coco betaine. See cocamidopropyl betaine coconut acid, 208 coconut fatty acid diethanolamide. See cocamide MEA coconut fatty acid monoethanolamide.

See cocamide MEA

coconut fatty acid triethanolamide. See cocamide MEA coconut oils, 136,205, 218 codeine, 178, 183 coenzyme A, 127 coffee, 158 coffee creamers, 123 coffee-sweetening packets, 81 cold remedies, 178 collagen, 15. See also gelatin colloids, 115 color stabilizers, 12-14 colors, 105-124. See also dyes comedones, 164-165, 167 comfrey root extract. See allantoin complex carbohydrates. See modified starch, starch conditioners, 219-222 conjugated bonds. See resonance bonds cooling gels, 60 copolymers, 232, 236 copper sulfate, 194 corn starch. See modified starch, starch corn syrup, 32-33, 84, 99, 134. See also sugars corrosion inhibitors, 235 cosmetics, 4, 12,20,22,25,36,37,39, 42,55,62,65,80,98, 102, 112, 113,186,218,222 cough products, 60, 178, 187

COX-1 enzymes, 183-184

Index

COX-2 enzymes, 183, 184

COX-3 enzymes, 183

cream, 130, 212 cream of tartar. See potassium bitartrate, potassium hydrogen tartrate creams first-aid, 172 hemorrhoid, 130 shaving, 217 skin, 57, 58,60,222 skin-lightening, 170, 194 crocetin, 117

Crocus sativus, 11 7

crystallization modifier, 88 cucumbers, 167 cuprous iodide, 28

Curcuma longa, 118

curcumin. See turmeric curry, 118, 167 custards, 148 cuticles, 203

Cyamopsis tetragonoloba, 98

cyanide poisoning, 40 cyclamates, 80 cyclic aminomethyl propanol, 160 cyclohexane, 228 cyclomethicone, 203. See also silicones cyclooxygenase inhibitors, 183, 184 cyclopentasiloxane, 235. See also silicones cystine, 123

D-glucitol. See sorbitol D-mannitol. See mannitol

Dactylopius coccus, III

Index

dairy products, 106, 115, 130, 141, 143, 212 dandruff medications, 166 DEEDMAC. See diethyl ester dimethyl ammonium chloride deer repellants, 70 denatonium benzoate, 56, 63, 69-70, 174 density balancers, 80 dental additives, 239-244 dental rinses, 243, 244 deodorants, 22, 26, 65, 215 deodorizers, 60 desiccants, 240 desserts, 77, 81,141 detergent bars, 209 detergents, 19,25,46--47,49-50,53, 129,136,139,185,196,197,200, 201,204,206,209,210,211-215, 241-242 dextrins, 87, 146-147 dextromethorphan, 178 dextrose, 155. See also glucose, sugars dibutylated hydroxytoluene. See butyl- ated hydroxytoluene diet products, 81,139,148 diethanolamine, 214, 218 diethyl ester dimethyl ammonium chlo- ride,213 diethylene triamine pentaacetic acid, 50-51. See also pentasodium pentetate diglycerides, 65, 93,100,132-134,154.

DNA fragments, 140

dodecyl ammonium sulfate. See ammo- nium lauryl sulfate dodecyl hexadecanoate. See esters dopamine, 158 dough conditioners, 46,148,151-156 drug coatings, 113, 120 dyes, 50, 51, 105-124, 164,208-209,

EDTA,213

electrical cables, coating, 70 electrophoresis, 140 emollients, 57, 58, 84, 222 emulsifiers, 46, 55, 57, 65, 80, 93, 99-100,115,123,129-134,135, 136,150,152,154,201-202,209, 212,217,222,235 endomorphins, 179 endorphins, 179

enzymes, 32,35,66, 76,87-88,96,127, 142,147,153,160,168,183-184 ephedra, 157. See also ephedrine ephedrine, 159-160. See also ephedra, pseudoephedrine epinephrine, 160. See also adrenaline erioglaucine, 113, 121. See also FD&C

Blue#1

erythorbic acid, 1, 15,40. See also ascor- bic acid erythrosin B, 112, 113. See also FD&C

Red #3

esters, 6-7, 61-62, 68-70, 80,106,130, 146,172,188,202,213-214 ethane, 225 ethanediol. See ethylene glycol ethanol, 55-56, 71, 172-173. See also alcohols ethoxylated ethyl 4-aminobenzoic acid (PEG-25 PABA). See para-amino benzoic acid ethyl alcohol. See ethanol ethyl p-aminobenzoate. See benzocaine ethyl PABA. See benzocaine ethyl salicylate. See methyl salicylate ethyl vanillin, 68, 69, 134 ethylene, 232-233 ethylene diamine tetra acetic acid, 49-50 ethylene glycol, 43 ethylene oxide, 200 ethylidenelactic acid. See lactic acid eutrophication of water, 47

fabric softeners, 220 fast green, 113. See also FD&C Green #3 fat-soluble vitamins, 96, 97

Index

253 fat substitutes, 95-103, 143, 145 fats, 91-103 long-chain, 131 omega-3 polyunsaturated, 95 polyunsaturated, 23, 92, 94 saturated,92 unsaturated, 92 fatty acids, 65-66,133,136,164-165, 208-209,212,218 long-chain, 62, 65,97

FD&C (food, drug, and cosmetic col-

ors), 112,113-115 FD&C Blue#l, 113, 121. Seealsoeri- oglaucine FD&C Blue #2, 113, 121. See also indig- otine, indigo FD&C Green #3, 113. See also fast green FD&C Red #3, 112, 113. See also ery- throsin B FD&C Red #4,119. See also Scarlet GN FD&C Red #40, 80,112,113,115,119.

Index

fluorides, 240-241, 243-244 foam peanuts, 147 foam stabilizers, 136,217-218 foaming agents, 200, 201, 223 folic acid,S, 154 food, drug, and cosmetic colors

(FD&C),113-115

foods bleaching, 195 canned, 77 coloring, 113-115 frozen, 27-28 packaging, 65 formaldehyde, 36, 39, 42, 202 free glutamates, 72-73

Freon, 224

fructose, 18, 31-33. See also sugars fruit acid. See glycolic acid fruits canned, 13, 14, 15,77 dried, 58, 195 fumaric acid, 47, 66-67, 68, 152 fungicides, 13,23,24,25,26,27,35,37, 80,165,192,195,196,202-203 furcellaran. See alginates

galactose, 81, 82, 98,101-102,139,148.

Index

255 homosalate.

See homomethylsalicylate honey, 1,17-18 hospital scrubs, 26 hot dogs, 120, 145 HSH.

See hydrogenated starch hydrosylate humectants, 43, 84, 85, 87,126, 155, 201-204,235 hydrated silica, 239-240, 241 hydrocarbon chains, 65 hydrogen peroxide, 18,21,164, 168-169,193-194,196,197,215, 242 hydrogen sulfide poisoning, 40 hydrogenated saccharides, 87 hydrogenated starch hydrosylate, 87 hydrogenation, 87, 93 hydrolysis, 140 hydrolyzed vegetable protein.

See monosodium glutamate hydrolyzing, 72, 87 hydrophilicity, 65, 146, 200, 211-212, 214,232 hydrophobicity, 65, 145,200,212-213, 232 hydroquinone, 169-170, 194 hydroscopicity, 85 hydrotropes, 139,202 hydroxyl groups, 65, 81, Ill, 146-147, 160 hydroxymethyl-2-propylamine.

See aminomethyl propanol hydroxymethylcellulose.

See methylcel- lulose, sodium carboxymethyl- cellulose hygroscopic acids, 67 hygroscopicity, 29, 34, 43,126,191 hyperpigmentation, 194

Index

ibuprofen, 183-184 ice cream, 19,20,27,64,81,98-101, 102-103,123,132,133,138,141, 148 icings, 130 imidazolidinyl urea, 36, 39,42,202 indigo, 114, 121

Indigofera tinctoria, 121

indigotine, 113, 121. See also FD&C

Blue #2, indigo

inhalers, 60 inner salt. See cocamidopropyl betaine inositol, 1 instant breakfast drinks, 148 intestinal flora, 145 intestinal relaxants, 40 invert sugars, 32-33, 114. See also sugars iodine, 28 Irgasan DP 200. See triclosan iron, 154, 168 iron (II) di-D-gluconate. See ferrous gluconate iron supplements, 124

Isatls tinctoria, 121

isoamyl 4-methoxycinnamate. See isopentenyl-4-methoxycinna- mate isobutane, 224, 225-226. See also butane isobutanolamine. See aminomethyl propanol isoleucine, 123 isomers, 15, 83, 160, 226 isopentenyl-4-methoxycinnamate, 10 isopropanol, 56 isopropyl palmitate, 204 isothiazolinone, 38-39, 203. See also methylisothiazolinone, methylchloroisothiazolinone

jams, 22, 142 jellies, 139, 142

Jell-G,141

jojoba oil. See esters juices, 22

kathon. See isothiazolinone kelp extract. See alginates keratolytic, 166, 168

L-alpha-aspartyl-L-phenylalanine

methyl ester. See aspartame I-glutamic acid. See monosodium gluta- mate

L-Iysine,90

lactic acid, 1, 39-40, 82, 114, 151-152, 165 lactose, 33-34, 82. See also sugars lakes, 113-114 lanolin, 62. See also esters LAS. See linear alkyl benzene sulfonates laughing gas. See nitrous oxide lauric acid, 130 lauryl diglucoside. See lauryl glucoside lauryl glucoside, 205, 214 lauryl palmitate. Seedodecyl hexadec- anoate lauryl sarcosinate, 241 laxatives, 139 lead, 50 leavening agents, 67

lecithin, 1, 20, 99-100, 154 lemon juice, 193-194 leucine, 122 Lexol 300. See triclosan lichenic acid. See fumaric acid lidocaine, 70, 173-174 linear alkyl benzene sulfonates, 214 liniments, 186 linseed oil, 94, 95 lipids, 96 liquid hand soaps, 202 liquors, 60 locust bean gum, 98,100,101-102,103 long-chain acrylic polymers, 46 long-chain alcohols, 6, 62, 203 long-chain polysaccharides, 102, 148 lubricants, 57,65,222 lycine, 122 lycopene,108-109 lye. See sodium hydroxide

M-dihydroxybenzene. See resorcinol rna huang. See ephedrine

Magic Rocks, 240

magnesium, 46, 49-50, 52, 53, 201,209, 242 magnesium carbonate, 29 magnesium salts, 100 magnesium silicate, 29 magnesium sulfate, 169 malic acid, 166 malting, 153 maltitol, 33, 86, 87 maltitol syrup, 87 maltitriitol, 87 maltodextrins,87, 146, 147 maltose, 33-34. See also sugars

Index

257 manna sugar.

See mannitol mannite.

See mannitol mannitol, 33, 83, 84-85 mannose, 98,101-102 mannuronic acid, 143 mannuronic chains, 143 margarine, 106, 107, 130 marshmallows, 141, 150 mayonnaise, 20, 27,129,130,212 MEA.

See mono ethanol amine meats, 28, 40, 41,115,123,145,171 medicines, 40, 58-59, 81,86,98, 120, 129,141,160,163-189 melanin, 170, 194 melissyl alcohol.

See triacontanol menstrual cramping, 184 menthol, 59-60, 86, 187 mepivacaine, 175 mercury, 49-50 metabolism, 34 metallic silicate, 240 metals, 49-50, 51, 52,112,168-169,240 methacrylate, 235, 236-237.

See also polymethyl methacrylate, octyl- acrylamide/acrylates/butyl- aminoethyl methacrylate copolymer methadone, 178 methane, 225, 227 methanol, 56, 78, 167 methionine, 123 methyl 3-pyridinecarboxylate.

See methyl nicotinate methyl 4-hydroxybenzoate.

See methyl paraben methyl ester.

See methyl nicotinate, methyl salicylate methyl groups, 14, 159

Index

methyl methacrylate, 233, 236 methyl nicotinate, 187-188 methyl paraben, 37 methyl salicylate, 167,185-186. See also oil of wintergreen, salicylic acid methyl sweet birch oil. See methyl sali- cylate methyl vanillin, 68, 69 methylcellulose, 100, 137-138 methylchloroisothiazolinone,38-39,

See glycerol monostearate

monomers, 143,232,236 monosodium glutamate, 71-73, 235.

N-(4-chlorophenyl)-N'-(3,4-

dichlorophenyl)urea. See triclo- carban N-acetyl-para-aminophenol. See aceta- minophen N-coco alkyl derivatives. See cocamide

MEA

N-[N- (3,3-dimethylbutyl)-L-ex-

aspartyl] -L-phenylalanine 1- methyl ester. See neotame

N-nitrosamines,40

n-octadecanoate. See stearic acid n-octadecylic acid. See stearic acid N-propyl gallate. See propyl gallate nail polish, 3, 70 naproxen,184 naproxen sodium. See naproxen nasal sprays, 86 natacyn. See natamycin natamycin,24 Neosorb. See sorbitol neotame, 33, 76-77, 80 neurotransmitters, 72, 158 niacin, 154, 188 niacin methyl ester. See methyl nicotinate nicometh. See methyl nicotinate nicotinic acid, 188 nitratine. See sodium nitrate nitric acid, 58 nitric acid sodium salt. See sodium nitrate

nitrites, 171 nitrogen, 171 nitroglycerin, 59 nitrous acid sodium salt. See sodium nitrite nitrous oxide, 134, 223-224 nonstick cooking sprays, 20 nonyl phenol. See alkyl phenoxy poly- ethoxy ethanols nonyl phenoxy ethoxylate. See alkyl phenoxy polyethoxy ethanols noradrenaline, 160. See also norepinephrine norbixin, 106 norephedrine. See phenyl- propanolamine norepinephrine, 160-161. See also noradrenaline novocaine, 70, 173 o octadecanoic acid monoester with 1,2,3-propanetriol. See glycerol monostearate octadecyl alcohol. See stearyl alcohol octadecyl octadecanoate (stearyl stearate). See esters octane, 228 octocrylene, 9 octyl p-methoxy cinnamate, 5 octylacrylamide/acrylates/butyl- aminoethyl methacrylate copolymer

Index

259 oils, 8, 60, 94-95,136,148-149,154, 167,203,205,208-209,215,218, 242 ointments, 186

Olestra, 95-96

oleyl alcohol, 203 olive oil, 149 olives, 124, 143 onion rings, 143 opiates, 178, 183

Orange B, 113, 120

orthostatic hypotension, 184 oxidation, 164, 191 oxybenzone, 8 oxycodone, 178 oxygen free radicals, 15, 16, 17, 21, 94, 105,107,165 ozone layers, 11

p-aminobenzoic acid. See para-amino benzoic acid PABA, 1,6-7,11,70. See also para- amino benzoic acid

PABA esters, 6-7

padimate A, 7 padimate 0, 7 pain relievers, 158, 170-189 paints, 44, 70,112,129 acrylic, 234 latex, 232, 236, 237 oil, 94 palm acid, 208 palmitic acid, 15,62 panthenol,126-127,203,235 pantothenic acid, 127,235. See also vita- min B papillomavirus, 167

Index

para-acetyl-amino-phenol. See aceta- minophen para-amino benzoic acid, 5-11, Ill,

Parkinson's disease, 184

pasteurization, 1 PDMS. See polydimethylsiloxane pectic acid, 142 pectin, 141-142 pectinic acid, 142 PEG. See polyethylene glycol esters

PEG-5 cocamide, 136,201

PEG-6 methyl ether, 209

PEG-no See polyethylene glycol

pellagra, 188 pentane, 226-227 pentasodium pentetate, 19,50,53,209.

See polysorbate 80

polypropylene, 233 polypropyline glycol, 136-137,242 polyquaternium-IO,204 polysaccharides, 98,101-102,138,139, 142, 149.

See modified starch, starch polysiloxane waxes, 222 polysorbate 60,132 polysorbate 65, 132 polysorbate 80,130-131,131-132 polystyrene, 233 polytetrafluoroethylene, 234 polyunsaturated fatty acid salts, 23 poly(vinyl acetate).

See vinyl acetate polyvinyl alcohol.

See vinyl alcohol polyvinylchloride, 233 potassium, 89-90,171 potassium bitartrate, 68 potassium bromate, 156 potassium chloride, 89-90.

See also salt potassium hydrogen tartrate.

See potas- sium bitartrate potassium iodate, 155 potassium iodide, 28 potassium nitrate, 170-171 potassium persulfate, 155 potassium salt.

See potassium bromate potassium sorbate, 23, 80 potassium stearate, 208 potato chips, 96 PPG-166/66 copolymer.

See polypropyl- ine glycol PPG-n.

See polypropyline glycol preservatives, 1-44,37,171,202-203, 209,235 prilocaine, 173, 175

Index

261 procaine, 173-174 progelatinization,147 proline, 122 propane, 224, 226 propanediol. See propylene glycol propanol, 56 propellants, 134,223-229,235 propionates, 34-35

Propionibacterium acnes, 164-165

propyl 3,4,5-trihydroxybenzoate. See propyl gallate propyl ester. See propyl gallate propyl gallate, 20-21 propylene, 233 propylene glycol, 29, 43, 126,202. See also glycols propylene glycol alginate, 143 prostaglandin, 183 proteins, 99, 124, 140, 153,214 provitamins, 127 pseudoephedrine, 157. See also ephedrine psoriasis medications, 166, 168 puddings, 106, 130, 145, 148 PVA. See vinyl acetate, vinyl alcohol Pvc. See polyvinylchloride

PVM/MA copolymer, 242

pyridoxine, 73 pyrophosphates, 136, 137,242 pyrrolidones, 213

quaternary ammonium compounds, 204 quaternium-5,204 quaternium-15. See alkyl ammonium chloride quaternium-18,204

Index

quats. See quaternary ammonium com- pounds quicklime. See calcium hydroxide

Quillaja saponaria, 207

raisins, 167 red cabbage, 109 reflectors, 11 refrigerants, 229 resonance bonds, 7-10, 108, 113 resorcinol, 164, 167-168 riboflavin, 154 rice, 107 root beer, 186 ropivacaine, 175 rubber, 65 rubefacients, 186, 187, 188, 189

saccharin, 32-33, 80, 81 safflower oil, 94 saffron, 105, 106, 107, 114, 116-117 saffron carotenoids. See saffron salad dressings, 20, 22, 27, 98,102,138, 150,212

Salatrim, 96-97

salicylates, 9-10 salicylic acid, 164-165, 166-167, 168,

Sapindus mukorossi, 207

Saponaria officinalis, 207

saponification, 208, 212 saponin, 207 sarcosinic acid, 204 sauces, 98, 102, 129, 138, 143, 145, 150 sausages, 120, 145 Scarlet GN, 119. See also FO&C Red #4 scopalomine, 178

SO-40, 56, 70, 174

SO alcohoI40-B. See ethanol SOle. See sodium dichloroisocyanurate seaweed extract. See agar, carrageenan sequestering agents, 19,49-54,242. See also water softeners serine, 123 shampoos, 26, 28, 37, 39,42, 57,60,62, 127,136,139,200-204,205,206, 209,211,214,217,218,236 shellac, 62 sherbet, 100 shingles, 173 short glucose chains, 87 shortening, 93 silica gel. See hydrated silica silicic acid. See hydrated silica silicon, 221 silicon dioxide, 29 silicone oils, 203. See also silicones silicones, 203, 220-222, 235 skin-care products, 3, 57, 62,126,130, 185,200,204,208 skin extract. See gelatin

Slime, 236

snacks, 145 soapbark. See Quillaja saponaria soapberry. See Sapindus mukorossi soaps, 2, 19,25,26,47,49-50,51,52, 53,65,84,185,202,207-209, 210,212-213,214. See also sodium stearate

soapwort. See Saponaria officinalis soda. See sodium carbonate soda ash. See sodium carbonate soda nitre. See sodium nitrate sodium, 47, 89,143,151 sodium 2-hydroxyethanesulphonate.

See sodium isethionate

sodium-2-pyrrolidone carboxylate. See sodium PCA sodium 4-dodecylbenzenesulfonate. See sodium dodecylbenzenesulfonate sodium aluminosilicate, 29 sodium benzoate, 1,21-22,67,80,203, 235 sodium biborate. See borax sodium bicarbonate, 29, 47, 67, 68,169, 242 sodium bisulfite, 13-14, 15 sodium borate decahydrate. See borax sodium carbonate, 19,29,50,51,52,53, 197,213,215,242 sodium carbonate peroxide, 193-194, 197,215,242 sodium carboxymethylcellulose. See methylcellulose sodium caseinate, 123. See also caseinates sodium chloride, 27-29, 40, 193,202.

Index

263 sodium dimethylbenzenesulfonate.

See xylenesulfonates sodium dodecylbenzenesulfonate, 209, 210,213 sodium EDTA, 19, 51, 52, 53.

See also ethylene diamine tetra acetic acid sodium ferrocyanide, 29 sodium fluoride, 241, 243-244 sodium glutamate.

See monosodium glutamate sodium hydrogen sulfite.

See sodium bisulfite sodium hydroxide, 123, 151, 191, 193, 207-209 sodium hypochlorite, 147, 191-195 sodium isethionate, 209, 211.

See also sodium cocoyl isethionate sodium lauryl sarcosinate, 204 sodium lauryl sulfates, 202, 241 sodium monofluorophosphate, 241, 243,244 sodium nitrate, 40, 41 sodium nitrite, 40-41 sodium palmate, 208 sodium PCA, 126,235 sodium perborate, 193, 196-197 sodium percarbonate.

See sodium car- bonate peroxide sodium peroxide, 193 sodium phosphate, 47 sodium propanoate.

See sodium propri- onate sodium proprionate, 35-36 sodium pyroborate.

See borax sodium pyrophosphate.

See tetra- sodium pyrophosphate sodium saccharin, 242

Index

sodium salt.

See sodium bisulfite sodium saltpeter.

See sodium nitrate sodium silicate, 169,240 sodium silicoaluminate.

See sodium aluminosilicate sodium stearate, 206-207, 208, 214.

See also soaps sodium stearoyl fumarate, 152.

See also sodium stearoyllactylate sodium stearoyllactylate, 151-152, 154-155.

See also sodium stearoyl fumarate sodium sulfate, 215 sodium suihydrate.

See sodium bisulfite sodium tallowate, 208 sodium tetraborate decahydrate.

See borax sodium thiosulfate, 29 sodium xylenesulfonate, 213.

See xylenesulfonates soft drinks, 19,22,47,77,79-80,81, 115,119,149,150,157-158 solvents, 215, 229 sorbet, 101 sorbic acid, 23 sorbitan monostearate, 129-130, 131 sorbitol, 33, 83-84, 85, 87, 96, 124, 126, 130 sorbitol syrup, 87 soups, 115, 145 sour cream, 141 soy lecithin, 131 soysauc~72, 115,235 soybean oil, 95 soybeans, 1 SPAN 60.

See sorbitan monostearate Splenda.

See sucralose spores, 192, 195 sports drinks, 160 spray breath fresheners, 224 spreads, 143 stabilizers, 135-156 stannous fluoride, 241, 243,244 starch, 98, 102, 114, 143-145, 153-154 acetates, 147 carboxymethyl, 146 ethers, 146 modified, 80, 145-146 oxidized, 147 starch retrogradation, 146 stearalkonium chloride, 204 stearic acid, 64-66, 92, 97, 130, 151 stearophanic acid.

See stearic acid stearyl alcohol, 56-57, 203 stearyl stearate.

See octadecyl octadecanoate stews, 115 stimulants, 157-161 straight-chain alkyl benzene sulfonates, 201,213-214 straight-chain benezene sulfonates, 210

Streptomyces natalensis, 24

strokes, 184 structural elements, 31 structured triglyceride. See Salatrim stump removers, 171 styrene, 233 styrofoam. See polystyrene sublimation, 29 substrates, 114 sucralose, 33, 78-81. See also sugars sucrose, 18, 31, 34, 96. See also sugars, table sugar sucrose octaester. See Olestra

sucrose polyester. See Olestra sugar alcohols, 33-34, 83-88,96 sugar cane extract. See glycolic acid sugars, I, 18,28,29-34,70,75,79,81, 82,87,96,98,99,101-102,114, 124,134,138,139,142,144-145, 148, 149, 153, 155,205,213,215.

Yellow #6

suntan oils, 8 superoxide dismutase, 21 surfactants, 55, 65, 136, 139, 199-215, 217,219,241 amphoterIc, 214 anionic, 200, 214 cationic, 213-214 nonionic, 57, 214 sweeteners, 31, 32-34, 75-88, 134, 241-242 Sweet'N Low. See saccharin syneresis, 102-103 synthetic wax. See sorbitan mono- stearate syrups, 115

Index

table salt, 28-29, 191, 193. See also sodium chloride tabletop sweeteners, 77, 81

Taehardla laeea, 62

tagatose, 33. See also sugars tartaric acid, 47, 67-68 tartrazine, 113, 119. See also FD&C

Yellow #5

tea, 158 teeth, bleaching, 194 Teflon. See polytetrafluoroethylene tetra acetyl ethylene diamine, 194 tetracaine, 175 tetrafluoroethylene, 234 tetrasodium (1-hydroxyethylidene) bis- phosphonate. See tetrasodium etidronate tetrasodium diphosphate. See tetra- sodium pyrophosphate tetrasodium EDTA, 201, 209 tetrasodium etidronate, 19, 50, 51, 52, 53,209 tetrasodium pyrophosphate, 19,46-47, 50,51,52,53,242 theobromine, 79,157,158-159 thiamine, 154 thickeners, 31, 57,135-156,222, 241 threonine, 123 tin compounds, 169 tin fluoride. See stannous fluoride titanium dioxide, II, 12, 113-114, 209, 242 tocopherols, 14,235. See also vitamin E tomato products, 72

Index

toothpastes, 12,22,25,46-47,58,60, 65,77,81,86,136,137,169,171, 194,200,204,211,239,240-242, 243,244 tramadol, 178 trans-1 ,2-ethenedicarboxylic acid.

See fumaric acid trans-butenedioic acid.

See fumaric acid trehalose, 33-34.

See also sugars triacontanol,62 triacontanyl palmitate.

See beeswax tricalcium phosphate, 90 trichloro-2' -hydroxydiphenyl ether.

See triclosan trichlorocarbanilide.

See triclocarban triclocarban, 25-26, 209 triclosan, 25, 26, 209, 242 triethanolamine, 214, 218 triethanolamine salicylate, 10 triglycerides, 65-66, 92, 97, 207 trilinolein, 92, 93-94, 149 trilinolenin, 92, 94-95 trimethylsiloxysilicate, 222 trimethylxanthine.

See caffeine triple helix, 140 trisaccharides, 102 trisodium citrate.

See sodium citrate tristearin, 91-92 Trolamine Salicylate.

See tri- ethanolamine salicylate truth serums, 178 tryglycerides, 99 tryptophan, 123 TSPP.

See tetrasodium pyrophosphate turmeric, 105, 114, 117, 118 Tylenol.

See acetaminophen tyrosine, 123

ultrasounds, 146 ultraviolet light absorbers, 2-12 utolyzed yeast. See monosodium glutamate

UV-A,11

UV-B, 11

UV-c, 11

valine, 123 vanilla, 70-71,134 vanilla beans. See vanilla vanilla extract. See vanilla

Vanilla planifolia, 70-71

vanilla sugar. See vanilla vanillin, 71, 134. See methyl vanillin vasodilators, 40, 59, 188 vegetable gums, 135 vegetable oils, 154 brominated, 80,148-149 vinegars, 1, 13, 31, 115. See also acetic acid vinyl acetate, 231-232, 234, 236 vinyl acetate/crotonates/vinyl neodec- anoate copolymer. See vinyl acetate vinyl alcohol, 232, 236 vinyl chloride, 233 vinyl monomers, 232-234 violins, 141 viruses, 192, 195 vitamin A, 6, 107 vitamin B, 1,5,20, 188. See also pan- tothenic acid vitamin B5. See panthenol vitamin B6. See pyridoxine

vitamin C. See ascorbic acid vitamin 0, 11 vitamin E, 1. See also tocopherols vitamins, fat-soluble, 96, 97

wart medications, 166-167, 168 washing soda. See sodium carbonate water-based products, 3 water-resistant coatings, 62 water softeners, 46, 49-54, 209, 241-242. See also sequestering agents water-treatment plants, 44 waxes, 61-62, 228 welding, 229 wetting agents. See surfactants whey protein, 142. See also monosodium glutamate whipped cream, 130, 133-134,223-224 whipped toppings, 148 whipping agents, 151-156

Index

267 windshield fluid, 70 wines, 13-14,23,67, 123 wood sugar. See xylitol wound dressings, 143, 185

(x)-sorbitan mono-9-octadecenoate poly(oxy-1 ,2-ethanediyl). See polysorbate 80 xanthan gum, 98, 100, 102-103

Xanthomonas campestris, 103

xylenesulfonates, 138-139. See also ammonium xylenesulfonate xylitol, 33, 85-86 y yeasts, 13,22,23,36,80, 153, 192, 195, 203 yogurt, 82, 141 z zinc oxide, 11, 12

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