Fragrance, Flavors And Food Additives 4j5g4e

chapter gY

Fpagrallccs,

aDd Food THE PERFUME' INDUSTRY

^tEilfliI;

The manufacture of cerfume, cologne, and toilet water, collectively known as the fragrances, has undergone drastic changes in the past quarter century, prior to which perfumers were rrsually trained through apprenticeships in laboratories until, working with traditional materials in well-defined patterns, they achieved skill in mixing and blending. Only occasionally was a new and original odor developed, such as old spice, which immediately won spontaneous and favorable response from consumers. Not many people realize how complex the creation of an acceptable fragrance has become; it requires professional knowledge, skill, and experience, coupled with specialization in synthetic chemibtry's technical problems, followed by consumer testing. This change has resulted from a number of factors, for example: (I) increase in the number of available raw-material ingredients, both natural and synthetic; (2) a variety of new types of products requiring fragrances; (3)'innovations in packaging, especially aerosol sprays, virtually nonexistent before 1g50, and other new forms of dispensing such as perfume powders, cream sachets, gels, lotions, and sticks;(4) broadened channels and methods of distribution, including door-to-door seiling; and (5) phenomenal growth in.men's toiletries. These numerous recent develdpments are in contrast to the two main changes which took place earlier, the introduction of synthetics and improved methods of ot,tainirrjtrue oils, Perfume takes its iarne from the Latin word perlumara (to fill with smoke), since in its original form it was incense burned in Egyptian temples. Early incenses were nrerely mixtures of finely ground spices held together by,myrrh or storax. The next advance was the discovery that; if certain spices and flowers were steeped in fat or oil, the fat or oil would

retain a portion of the odoriferous principle. Thus were manufactured the ointments un{ fragrant unguerrts of Biblical fame. Avicenna, the Arabian physician, discovered steanr distillation of volatile oils. During his search for medical potions, he found that flowers boiled tlr an alembic with water gave up some of their essence to the distillate. The returning Crusaclers brought to Europe all the art and skill of the orient in perfumery, as well as informuti6n relating to sources of gums, oils, and spices. Ren6, perfumer to Catherine de' Medici, invented many new confections to delight the queenly nose and, in l-ris spare time, was one of the cleverest and deadliest of the famirus de' Medici poisoners. N,lany of the finest perfumes ure imported from . Classical colognes are at least 200 years old, having originated irr

IECT, Bd ed., vol 16, 1982, p.947.

4M

The Perfume

Induslry

485

Cologne, ; they were probably the first imports into this country. It u'as not ur:til the I950s that U.S; industry discovered that the sale of perfume odors in an alcohol-diluted form was profitable. UsEs d/vD ECaNoLrIc& Fragrance shipments were $1800 million in lg8l, and this was a large iricrease from the $320 million in I974, The popularity of men's fragrances has, no doubt, contributed greatly to the increase Fragrances make a major contribution to the cosmetic industry, second only to the amount used in soaps and detergents. Fragrances are used industrially in masking, neutraliring, and altering the odor of various products, as well as in creating a'distinctive aroma for normally odorless objects. Cashmere shawls manufactured in Scotland are given the Hindu touch by a trace of patchouli oil applied to them. Aromatics, sometimes referred lo as reodorants, are added to fabric sizing to disguise the glue or casein smell, leaving the product with a fine fresh odor. Leather goods and papers are scented delicately to eliminate the raw-material smell. The odor of kerosene in fly sprays is masked; artificial cedarwood is made by coating other woods with cedar oil reclaimed in pencil manufacturing. Canneries, rendering plants, municipal refuse plants, and food processing systems are other areas where reodorants are used- Paint odor during drying is masked by essential oils and fixatives introduced in small quantities in the bulk product. Odors are used successfully to increase customer appeal, though they are not essential to the performqnce of the.products to which they are added,2 A minute amount of bornyl acetate evaporated in an air-conditioning system imparts an out-

door tang to the air.

"ttConstituents A perfume may be detined as any mixture of pleasantly odc,rous substances incorporated in all the products used in perfumery were of natural origin. Even when humans first started synthesizing materials for use in this field, they errdeavored to duplicate the finest in nature..Theri has been a marked tendency in'recent years, however, to rnarket perfumes which have no exact counterpart in the floral kingdom but which have received wide acceptance. The finest modern perfumes are nerther wholly synthetic nor completely natural. The best product of the art is a judicious blend of the two in order to enhance the naturaL perfume, to reduce the price, and to introduce fragrances into the enchantlng gamut at present available. A product made solely of synthetics tends to be coarse and unriatural because of the absence of impurities in minute amounts which finish and round out the bouquet of natural odors; however, such an eventual development is predicted. The chemist has also succeeded in creating essences of flowers u,hich yield no natural essence orwhose essence is too expensive or too fugitive to make its extraction profitable. Lily of the valley, iilac, and violet are examples. The constituents of perfumes are: the vehicle or solven(, the fixative, and the odoriferous elements. a suitable vehicle. Formerly, practically

vEnrcLxs. The modern solvent for blending and holding perfume materials is highly refined ethyl alcohol mixed with more or less water according to thesolubilities of the oils employed. This solvent, with its volatile nature, helps to project the sceDt it carries, is fairly inert. to the zMitchell et al., "lmportance of Odor as a Nonfunctional Component," Odor Symposium, New York Academy of Sciences, Novembef 7*9, 1903.

',ltf t" rC S

486

Chap.27 Fragrancec, trlavo?a, and food Addlttvce

The

irritating to the human skin, The slight natural odor of the alcohol is or "prefixation," of the alcohol. This is accomplished by adding a by deodorizing, removed small amount of gum benzoin or othir resinous ftxatives to the alcohol and allowing it to mature for a *eek o. two. The result is an almost odorless albhol, the natural rawness having solutes, and is not too

If solution is brought about in the cold, the mixture istalled a tincture.If heat is required to give solution, the mixture is an infusion Alcohol is the solvent, sometimes aided by benzyl benzoate or diethyl phthalate. The most important of the soft gums is Labdanum. The Ieaves of a plant growing in the Mediterranean area exude this sticlly substance. An extract from thisgum has an-odor suggestive of ambergri's and is marked as ambrein, having extremely good fixative value. Of the harder plant resins used in perfumes, benzoin is the most important. The history of chemistry was influenced by this substance. The early source of benzoin was Java, where it was called luban iau:i. Through various contractions and linguistic modifications, it became "banjawi," "benjui," "benzoi," "benzoin," and "benlamln." In early organic chemical history an aeid isolated from this gum became known as benzoic acid, [rom which compound the names of all benzo compourrds of today are derived.

a brownish orange exu-

date of the perineal glands of the beaver, is employed in the greatest quantity. Among the odoriferous components of the volatile oil of castor are benzyl alcohol. acetophenone, l-borneol, an
Essential-Oil Fixatioes, A few essential oils are used for their fixative properties as well their odor. The more important of these are clary sage, vetiver, patchouli, orris, and san' dalwood. These oils have boiling points higher than normal (2S5 to ZSOog;. as

for export in hollow horns. The crude civet is disagreeable

in ojor because of the skatole present. On dilution and aging, however, the skatole odor dis-

Sgnthetic Firathses. Certain high-boiling, comparatively odorless esters are used as ffxatives to replace-some imported animal fixatives. Among them are glyceryl diacetate (25goC), ethyi phthalate (2950C), and benzyl benzoate (323"C).bther synt-hetics are used as fixatives,

appears, and the sweet and somewhat floral odor of civetone, a cyclic ketone, appears. CH.(CH^),

"')co llcH-(cH2\7/

487

Peru balsam, tolu balsam, copiaba, and storax; oleoresins, oily materials, e.g., terpenes; extracts from resins, less viscous, e.g., ambrein. All these substances, when being pr"p..Ld fo. oerfume compounding, are dissolved and aged by methods ed down by word of mouth.

substances in alcohol, the more volatile mateperfume consists of a series of irnpressions r.atherthan of the odor and the first, evaporate rials the desiied ensemble. To obviate this difficulty, a ffxative is added. Fixatives may be defined as substanqes of lower volatility than the perfume oils, which retard and even up the rate of evaporation of the various odorous constituents. The types of fixative considered arplanimal ,""iitiorr., resinous products, essential oils, and synthetic chemicals. Any of'these fixatives may or may not contribute to the odor of the finished product but, if they do, they must blend with and co,,rplement the main fragrance.

4 days by spooning,and are packed

Indu.tty

Recinous Fitatioea Resinous ffxatives are normal or pat'hological exudates from certain plants, which are more important historically tharr commercially.-These are hard resins, e.g., benzoin and gunrs; softer resins, e.g., myrrh and labdanum; balsams, moderately soft, e.;.,

FrxATrvES In an ordinary solution of perfume

Anirwl Firotiaes. Of all animal products, castor, or castoreun't,

per!tume

//\-CH" cH3-c{ ,co

although they have a definite odor of their own that contributes to the ensemble in which they are used. A few of these are

jcfi,),,

Amyl

benzoate

Phenethyl

phenylacetate

Cinnamic alcohol esters Cinnamic acid esters

Musk is the dried secretion of the preputial glands of the male musk deer, found in the Himalayas. The odor is due to a cyclic ketone called muslane, which is present to the extent of from Yrto ZVo. Musk, the most useful of the animal fixatives, imparts body and smoothness to a perfilme composition even when diluted so that its own odor is completely effaced. Musk is used for its own sake in heavy oriental perfumes. Arnbergris .is the least used, but probably best known,. of the animal fixatives. It is a calculus, or secretion, developed by certain whales. Ambergris is obtained by cutting open the captured whale, or it is obtained from whales stranded on a beach. It is waxy in consistency, softening at about 60oC, and may be white, yellow, brown, black, or variegated like marble. It is composed of 80 to 85% ambrein (triterpenip tricyclic alcohol), resembling cholesterol and acting merely as a binder, and 12 to 15% amb'ergris oil, which is the active ingredient. It is employed as a tincfure, which must be rnatured before it is used. The odor of .the tinctuie is decidedly musty and has great fixative powers. Masf zibata is the newest animal fixative, derived from glands of the Louisiana muskrat. It was only during: World War II that musc zibata was commercialized. About 90% of the unsaponiffabie material in muskrat glbnds consists of large, odorless cyclic alcohols, which are converted'to ketones, increasing the characteristic musk odor nearly 50 times. It is a replacement for, or an addition t6, Asiatic musk.

Acetophenone

Musk Musk

ketone ambrette

Benzophenone

Vani.llin

Heliotropin Hydroxycitronellal Indole Skatole

Coumarin

oDonous suBsreNCES. Most odorous substances used in perfumery come under three headings: (1) essential oils, (2) isolates, and (B) synthetic or semisynthetic chemicals. Ecsential Oils.8 Essential oils may be defined as volatile, odorilerous oils of vegetable origin (Table 27.1). A distinction should be made, however, between natural

flower,oils

obtained by enfleurage or solvent extraction and essential oils recovered by distillation. Distilled oils may lack some component which is not volatile enough o, *ti"t is lost during dlstillation. Two notable examples of this are rose oil, in which pni"ryutr,fr *icohol is lost to the watery portion of the distillate, and orange flower oil, in which the distilled oil contains 3"Essential"

does not mean "most necessary' but rather the concentrated characteristic or quintessence of a natural flavor or fragrance raw material; Internatioital Standardtzatton

of

Essential oils, committee ISO/TCS4 publishes standards. see cosrnet. perfum.90 (2) g6 (r975). i

i

$

*

$

The Petfutne

Table

27.7 Important

Name of Oil

Almond, bitter

Sources

California,

Method of Production

Part of

Chief

Plant Used

Constituents

Steam

Kernels

Morocco

Benzaldehyde 96-98%, HCN 2-4% Eugenoi 50%

Bay Bergamot

West Indies Southern Italy

Steam Expression

Leaves Peel

Caraway

Northern EuroPe, Holland

Steam

Seed

Carvone 55%, d-limonene

Cassia (Chinese

C\ina

Steam

Leaves and

Cinnamic

North America Ceylon

Steam Steam

twigs Red core wood Bark

aldehyde 70% Cedrene, cedral

Linalyl acetate 40%, linalool 6Vo

cinnamon) Cedarwood

Cinnamon

Citronella,

Java

Clove

Java, Ceylon

Steam

Grass

Zanzibar,

Steam

Buds (cloves)

Cinnamic aldehyde, eugenol Geraniol 65%, Eugenol 85-95%

Steam

Fruit

Linalool, pinene

California, '

Steam

Leaves

Mediterranean countries , EgyPt,

Steam

Leaves

Cineole (eucalyptole) 70-80% Ceraniol esters

Cold poma,Je

Flowers

Russia

Eucalyptus

Australia

Cetanium Jasmtne

[,avender

30%, citronellol Benzyl acetate,

linalool, and

Italy Mediterranean

esters

Distillation

Flowers

Linalool

area

Lemon

California, Sicily

Expression

Peel

d-Limonene 90%, citral

Orange, sweet

Florida, California,

Expression,

Peel

d-Limonene

s.5-57 90%

distillation

Mediterranean area

Leaves and tops

Menthol 45-

Flowers

90% and esters Geraniol and

Steam

Wood

Santalol 90%,

Michigan, Indiana

Steam

Leaves

Carvone 50*

Tuberose



Enffeurage, solvent extraction

Flowers

Tuberose oil

Wintergr"en

Eastern United

Steam

Leaves

Methyl

Steam, solvent

Flowers

Esters, alcohols

.Stearn

Peppermint

Michigan, Indiana, etc.

Rose

Bulgaria, TurkeY

Eteam, solvent,

Sandalwood

India, East Indies

Spearmint

(gaultheria) YIang-ylang

75%

esters 3% 6OVo

States

Philippines

488

citronellol

enfleurage

Madagascar,

l. Esters, Mainly of benzoic, acetic, salicylic, and cinnamic acids 2. A.cohols, l,inalool, geraniol, citronellol, terpinol, menthol, borneol 3. Atilehydes. Citral, citronellol, benzaldehyde, cinnamaldehyde, cuminic aldehyde, vanillin

4, Acids.

Benzoic, cinnamic, myristic, isovaleric

in the free state

5. Phenols. Eugenol, thymol, carvacrol 6. Ketones. Carvone, menthone, pulegone. irone, fenchone, thujone, camphor, methyl nonyl ketone, metliyl

heptenone

7. Esters.

Indonesia

Central EurgPe,

contain as much as one-sixth of this constituent. Essential oiis are, in the main, insoluble in watet and soluble in organic solvents, although enough of the oil may dissolve in water to give an intetrse odor to the solution, as in the caSe of rose water and orange flower rarter. These oils are volatile enough to distill unchanged in most instances, and are also volatile with steam. They vary from colorless to yellow or brown in color. An essential oil is usually a mixture of comfounds, although oil of wintergreen is almost pure methyl salici,late. The refractive indexes of the oils are high, averaging about I,5. The oils show a wide range of optical activity, rotating in both directions. The compounds occurring in essential oils may be classified as follows:

citronellal

Madagascar,

,Coriander

489

bul a very small proportion of methyl anthranilat.:, whereas the extracted flower oil may

Important Geographical

Indwtry

;i:

Essential Oils

salicylate 99%

Cineole, internal ether (eucalyptole), anethole, safrole 8. Lactones. Ooumarin 9, Terpenes. Camphene, pinene, limonene, phellandrene, "edten" 10, HEdrocarbons. Cymene, styrene (phenylethylene)

lr h;

t TI

ffi

lr Sl

h ilr {!,

tFl,

lill

In living plants essential oils are probably connected with metabolism, fertilization, or protection {rom enemies. Any or all parts of the plant may contain oil. Essential'oils are lound in buds, flowers, leaves. bark, stems,'fruits, seeds, wood, roots, and rhizomes and ilr some trees in oleoresinous exudates. Volatile oils may be recovered from plants by a variety of methofls:a (1) expression, (2) distillation, (3) extraction with volatile solvents, (4) enfleurage, and (5) maceration. The majority of oils are obtained by distillation, usually with steam, but certain oils are adversely affected by the temperature. Distilled citrus oils are of inferior quality; therefore they are derived by expression. For certain flo*ers which yield no oil upon distillation or else deteriorated oil, the last three methods are used. However, extraction with volatile solvents, a comparatively recent process, has superseded maceration (extraction with hot fat) for all practical purposes und is replacing enfleurage. Solvent extraction is the most techhically advanced proand yields truly representative odors, but is more expensive than distillation, Disti,llation, usr.tally oith steam.. Flowers and grasses are normally charged into the still without preparation. Leaves and succulent roots and twigs are cut into small pieces. Dried materials are powdered. Woods and tough roots are sawed into small pieces or mechanidally chipped. Seeds and nuts are fed through crushing rolls spaced so as to crack them. Berries are charged in the natural state, since the heat of distillation soon develops enough pressure to cess

burst their integument. The stills employed in factories are of copper, tin-lined copper, or stainless steel and of about 2300 L capacity. They are provided with condensers of various sorts, tubular ones being the more efficient, and with a separatoi for dividing the oily layer from the aqueous cne. Although removable baskets for holding the material to be distilled are used, the better procedure seems to be to construct the still rvith a perforated false plate lying just above the bottom. Underneath this false bottom are steam coils, both closed and

extraction

aDorland and Rogers, The Fragrance and Flooor lndustrg" Dorland, Mendham, N.J'' 1977

qr

490

Chap.27 Ftattancca,Flavotc,andFoodAddltlvu

perforated. In operating these stills, the charge is heated by steam in both the closed and the open pipes, thus effecting economical steam distillation. The aqueous layer in the condensate in solution, valuable constituents, as in the cise of rose and orange flower t."qru.rily "^.ries, oil, and is consequently pumped back into the still to supply some of the necessary water. Steam distillation usually is carried out at atmospheric pressure. If the constituents of the oil are subject to hydrolysis, the process is carried out in a vacuum. Much distillation for essential oils is done-at the harvest site in extremely crude stills. These stills are converted oil drums or copper pots equipped with pfpe condensers running through water tubs. The material and water are charged into therstill, and a direct fire of dried material exhausted in previous distillations i.s built r.nderneath. The efficiency is low, and the oil is contaminated with pyrol'Ihe crude oils ysis products, such as acrolein, trimethylamine, and creosotelike substances. obtained from the stills arb sornetimes further treated before use by vacuum-rectification, by fractional freezing (e.g., menthol from Japanese'peppermint oil), by washing with potassium hydroxide to remove free acids and.phenblic compounds, by removal of wanted or unwanted ,id"hyd.r and ketones through formation of the bisulffte addition,compounds, or by formation of specific insoluble products, as in the reaction of calciirm chloride with geraniol. Expression by machine can yield an oil almost identical to the hand-pressed product, and ,is the method used eommercially. Of the hand-pressed processes, the sponge process is the most important, since it produces the highesrquality oil. Here the fruit is halved, and the peel trimmed and soaked in water for several hours. Each peel is pressed against a sponge, anci the oil is ejected into the sponge, which is periodically squeezed dry. One person can prepare only 680 g of lemon oil a day by this method, but it is still practiced, especially in Sicily. Enfleurage. The enfleurage process is a cold-fat extraction process used on a few types of delicate flowers (jasmine, tuberose, violet, etc.) which yield no direct oil at all on distillation. In the case of jasmine and tuberose, the picked flowers coritinue to produce perfume as long as they are alive (about 24 h). The fat, or base, consists of a highly purified mixture of I part tallow to 2 parts lard, with 0.6% benzoin added as a preservative. This method is no longer used commercially. Extraction with oolatile solDents. The most important factor in the success of this practice is the selection of the,solveht. The solvent must (1) be selective, i.e., quickly and completely dissolve the odopiferous components, bUt have only a miriimum of inert matter, (2) have a low boiling point, (3) be chemically inert to the oil, (4) evaporate completely without leaving any odorous residue, and (5) be low-priced and, if possible, nonflammable. Many solvents have been used, but highly purified petroleum ether is the most successful, with benzene ranking next. The former is specially prepared by repeated rectification and has a boiling point no higher than 75oC. When benzene is employed, it is specially purified by repeated crystallization . The ertraction equipinent is complicated and relatively expensive and consists of stills for fractionating the solvent, batteries for extracting the flowers, and stills for concentrating the flower-oil solutions. The two types of extractors employed are the stationary and

rotary types.

In the rotary pro3"s the oil is extracted on the countercurtent principle. The

1325-L steam-iacketed drums revolve around.a horizontal axis and are divided into compartments by pe*o$ated plates.at right angles to the axis. About 135 kg of flowers is charged into the first drum, along with 575 L of petroleum ether which hais already comq through the other two drums. The drum and-its contents are rotated for an hour cold and for qn additional half hour with steam in'the jacket. The saturated solvent is pumped to the recovery still, and the flowers in the drum are heated twiie more, the second time with once-used solvent and the last time with fresh solvent from the recovery still. The exhausted flowers are blown with

ThePerfumelndvdrY 497 steam to.recover the adhering solvent. About 90 percent of the solvbnt is boiled off at atmospheriq pressure, and the rest is removed under vacuum. After the solvent i$ removed in either p.o""rr, th" semisolid residue contains the essential oil, along r,r'ith a quantity of waxes, resins, and colbring material from the blossoms. This pasty mass is known as conclete. In turn it is treated with cold alcohol in which most of the wax and resin are insoluble. The small aiaount

of unwanted material that dissolves is removed by cooling the solutiou to -20"C and filtering it. The resulting liquid contains the essential oil and Some of the ether-soluble color of the flower and is known as an ertract. When the alcohol has been removed, an obsolute remains In some oils there is a large quantity of terpenes. This is especially true in the case of lemon and orange oils, which have as much as 9O% d-limonene in their normal composition. Not only are terpenes and sesquiterpenes of exceedingly little value to the strength and character of the oils, but they also oxidize and polymerize rapidly on standing to form compounds of a strong turpentine-like flavor. Furthermore, terpenes are insoluble in the lower strengths of alcohol used as a.solvent and make cloudy solutions which are cleared up only with difficulty' Hence it is desirable to remove terpenes and sesquiterpenes from many oils. Such an oil, orange, for example, is 40 times as strong as\he original and makes a clear solution in dilutb alcohol. The oil has now very little tendency to rancidify, although it has not quite the freshness of the original. These treated oils are labeled "tsf" (terpene- and sesquiterpene-free). Because each oil has a different composition, dete.rpenation requires a special process. Two methods are involved, either the removal of the terpenes, sesquiterpenes, and paraffins by fractional distillation under vacuum, or extraction of the more soluble oxygenated compounds (principal odor carriers) vrith dilute alcohol or other solvents. ^ Because 6f the complex nature and the high price commanded by so many essential oils, a great deal of adulteration, or sophistication, is practiced. These additions were formerly extremely hard to detect in most cases since, whenever possible, a nrixture of adulterants is used thai does not change the physical constants of the oil. Common agents used are alcohol, cedar oil, turpentine, terpenes, sesquiterpenes, and low specific gravity liquid petrohums. The advent of so many esters of glycol and glycerol on the market increased the difficulty of detectiorl, since these compounds are colorless and practically odorless and in the right combination can be made to simulate almost any specific gravity and refractive index specifications set up {or the oil they are intended to adulterate. The modern use of gas chromatography (GC) has made it possible to deiect easily even small amounts of adulterants. Rose oil may be sophisticated with geraniol br a mixture of geraniol and citronellol; wintergreen and sweet birch oil are mixed with large amounts of synthetic methyl salicylate; and lemon oil is often "stretched" considerably with citral from lemon grass oil.

lsolotes. Isolates are pure chemical compounds whose source is an essential oil or other natural perfume rnaterial. Notable examples are eugenol from clove oil, pinene from turpentine, anethole from anise oil, and linalool from linaloa oil (bois de rose). SyN?IIErTCS AND SEMISrNTIIETICS USED IN PE&FAMES AND FLAVO&S.S N4ore and more important constituents of perfumes and flavors are being made by the usual chemical synthetic procedures. Compositions containing predominantly inexpensive synthetics now for more than 50 percent of the fragrances used in perfumes. Some constituents are chemically synthesized from an isolate or other r.atural starting materials and are classed as sPoucher, Perfumes, Cosmetics and Soaps, vol. II, Wiley, New York, 1974; Clark and Grande, Study of Odor Variation with Structural Change, Cosrnet. Pertum.90 (6) 58 (19?5); Chemicals from Trees, CHEMTECH, 5 236 (1975).

,!l

ti lr

{l h {t *t

fi

492

Chap.

27 Fragrancea, Flavorc, and Fcioi! Addlttvcs The Perfume

semisynthetics. Examples ar.e vanillin, prepared from eugenol from clove oil; ionone, from citral from Iemon grass oil; and terpineols, from turpentine and pine oil. Some of the significant synthetics are discussed below. The examples presented are grouped under the'most

material, or the Hassmann-Reirner synthesis, where coumarin-3-carboxylic acid is produced intermediate. Over 450,000 'kg is produced per year. Diphen,Jl oxide, or ether, is largely used in the soap and perfume industries because of its great stability and strong geranium odor. Diphenyl oxide is obtained as a by-product in the manufacture o{ phenol from chlorobenzene and caustic soda.

Condencation procesieoa (Fig. 2Z.l), Coumarin occurg in tonka beans and 65 other plants, but.the economical source is the synthetic. It is employed as a fixative and enhancing agent for essential oils and tobacco products, and as a masking agent for disagreeable odors in industrial products. The synthetic product may be preparedT in a number of different ways. One method utilizes the Perkin reaction:

@:x:'HCooNa

453

as an

important chemical conversion.

O::'#ffiF

Industry

2C6H5OH:

CoHsOCoHs

*

H2O

Ionone and its homologs possess the so-called violet type of odor, thus constituting the base of violet perfumes. These compounds, however, are indispensable to fine perfumes, and there are but few which do not contain at least a small perbentage of ionones. Annually, about 225,000 kg of ionones is produced. Because of the high price of the natural oil of violet, this was'one of the fiist essential oils synthesized, although it has since been found in certain obscure plants. The olfactory properties of ionone are due-to the presence of dl-a;ionone and B-ionone. Their manufacture involves two steps: First, the pseudo-ionone is prepared by the condensation of citral obtained from lemon grass oil. This is followed by an acid ring closure, and the commercial ionone is purified by distillation. Commercial ionones are $enerally mixtures with one form predominating, although separations are sometimes made through bisul-

- @;-:,"

Salicy-laldehyde, acetic anhydride, and sodium acetate are refluxed at 135 to l55oC. The reat'tion mixture is cooled and washed. The coumarin is recovered by solvent extraction or distillation. Other important methods of coumarin preparation utilize o-cresol as the starting 6Process-studded

Plant: Key to Fragrance, Chem. Eng. 6i (4) I12 (195g) 7ECT,3d ed., vol. 7, 1979, p. 196.

[ite compounds.

,r4., ,r",,

Hrc,..,,,uH,,

cH, --c --c CH HC" I HC" CHCH: rtH(lo(tH-J -CHo + tt C:o 'i.11-.?]-, I I ll \aoH Hrc-'cH, Hri_-CH,-c- cHr i -l- cH. cH,

H2so{,

roao

r

H.C '\,/

PLANT l aTEntaLS.-Crushing,

_

"'|/.c

PRETREATMENT

H"C

grinding, chopping, eic

CHEM ICA L ru

r"r n],,r'i

5 iai

e S

._-.-+

n, h y d ro I e no ri o n, condensolion, ocelylolion, polymerizolion, etc. i

d,o

CH,,

CHCH:CHCOCH

i"*^

-l f H,C

H,C. '-c,

eCH:

CHCOCH;,

ll

-C

-

CH,,

p.k,ione

Cinnamic aldeh1de has a cinnamon odor. As it oxidizes in air to cinnamic acid, it should be protected from oxidation. Although this aldehyde is obtained frorn Chinese cassia oils, it is Synthesized by action of alkali upon a mixture of benzaldehyde and acetaldehyde (Fig. 27.2). The production is about 365,000 kg per year.

SYNTHES IS Or

H"C C

a.lonone

SOLVE NT EXTRACTION

P*udo.ionone

CH"

H,C. ' -cri-_\'.- CH"

I

r

Cirral

I io

ANIMAL PRODUCTS

C6HsCHO PURCHASED I,IATERIALS

+ CHsCHO.*C6HsCH:CHCHO *

H,O

This and most other products for fragrances must be purified, for example, by vacuum frac-

-roR hESALE Essentiol oils

tionation (Fig. 27.3).

Chem icols

Florol obsolutes Florol concrel€s

}S,-27t!tOu1!i1e flowchart for the manufacture of perfume 3nd flavoring materials. [Ind. Eng. Chem. 53 (6) 422 (7961); courtesg oJ Filtzsche Bros.l

I I I

t

Esterification Processes. Benzgl berizoalr has a faint aromatic odor, boils at 323 to 324oC, and is a fixative and a flavor:ng material. It occurs naturally in balsams (Peru, To16) but is,'prepared commercially by the esteriffcation of benzoic acid with benzyl alcohol or by the Cannizzaro reaction with benzaldehyde.

!:

!

494

The Perfumc

Chap..z7 Fragrnncee, Flavore, and Food Addlllvu

Indurtty

495

i.r '],ii$

:& ,'$ il

Two esters ol salicElic actd \o-hydroxy benzoic acid) are very important commercially in 'the perfume and flavoring industries. About 160,000 kg of am,ll salicAlate is used annually in a variety of perfumes, because of its lasting quality and low price. About 1.8 X 106 kg of t"rrethAl salicrJlate (synthetic wint'ergreen oil) is consumed annually as a flavoring ingredient.

benzoldehyde, colol ysl

'IheSe esters are prepared as follows: Carbon dioxide and sodium phenate are reacted under pressure to obtain the salt of phenylcarbonic acid. This salt is isomerized to sodium salicylate by heating to 120 to 140oC, The esters are made from-the acid and the proper alcohol. BenzEl acetate (C6H'CH2OCOCHs) is anothet widely used ester because of its low cost

and floral odor. About 450,000 kg is sold annually for soap and industrial perfumes. It is prepared by esterification of benzyl alcohol, by heating with either an excess of acetic anhydride or acetic acid with mineral acids. The prod.uct is purified by treatment with boric acid and distilled, giving a purity of over 98%. Large amount s of benzgl alcohol are employed in

Wosle lh gher polymers)

REACTOR NEUTRAL ]ZATION

SEPA. RATION

WASHING

I

FRACTIONAL DISTILLATION

Fig..27.2. Flowchart for cinnamic aldehyde'production by aldol condensation. (Fritzsche Bros

Inc.)

pharmaceuticals, iacquers, etc. (about 1.8 X 106 kg per year). This alcohol has a much weaker odor than its esters. It is made by hydrolyzing benzyl chloride' {1

I

{ Grignord Processes. Phenglethyl alcohol has a roselike odor and oocurs in the volatile oils of rose, orange flowers, and others. It is an oily liquid and is much used in perfume formulation, more than 450,000 kg being sold annually. Phenylethyl alcohol can be made by a number of procedures; the Grignard reaction is used generally:

'li, {.

i I

i T

i; c6HrBr -]"],EI!

c.H

rMgBrtU'aur,

ar rarroMgBr

-9f

ri

c6Hs . cH2cH2oH

However, the Friedel-Crafts reaction is outlinqd in the flowchart in Fig. 27.4 andfollows the leaction

CoHo B€nEne

Hgdrogenation.

See

Fig.

27

+

(cHz)2o

jEgc6Hs.

cH2cH2oH

Ethylene oxide

.5 f or citroiiellal from citronellol by Raney nickel hydrogen-

ation at 1375 kPa. CH2-C(CH2

)3-CH-CHr-611, gg --;;i

CH:

CH2-C-(CH2)3-qH-CH2-CHO

CH:

CH:

CH:

Citronellal

Citroneliol

Nitration Processes. Artificial musfts comprise a number of products not identical lvith the natural musk, which derives its odor from macrocyclic compounds. Nitro musks are practical and economical substitutes for this expensive natural fixative, and more than 90,000 kg o[ musk xylene alone is manufactured annually. The reactions for the three important commercial artiffcial musks are MUSX AMBNETTE

oH

rAl Fig. 27,3. High-temperature vaicuum fractionating equipment. (Frltzsche Inc.)

\2.n. Bros.,

ocH3

rlrtr% KoH aAt"

V.r,

(ctt.).co, (cHa)3c Atct3

, HNor .r, ffi

-.QCH, (cH3)3cal-\NO,

v.r. NO,

,i

N6

Thc Pcrfitme

Chap.27 Fts,t,|ance., Flavoeol hnd trood Addltlvat

Induby

457

Hydrogen

Elhylene oxidb

PRESSURE VESSEL

BATCH OISTIL LATION COLUMN

Fig.27.5. Hydrogenation under pressure of lB80 kPa to convert citronellal to citronellol. {Chem. Eng. 65 (4) (1958); courtesA ol Van Ameigen Haebler.l

Fig. 27,4. Phenylethyl alcohol formed by the FriedelCrafts reaction. lChem. Eng.85 (4) 113 (1958): courtesg Haebler.l

OH

ol Van Amertgen

OH

1fiot'" o*" \7, V CHrCH:OH, uou

MT]$(, XYLENE AND MASK I(,,TONE

CH:CHCHT

,

CH, ?0%

C6H/CH3)'

-l!ffig-

c6H3(cH3)2. c(Crr.l.

n.X;rlenc

ffi

Hzso.,

,.rrn

[9

ar,

xvr'ne cH.

CHO Vanilin.

Heliotropin, or piperonal, has a pleasant aromatic odor resembling heliotrope. duced from safrole by the following reactions:

**',,,..o'*fAtotn' qP, . c6H2(cH3)2.c(cH3)3.cocH3 _r___r,r _,___r ,ltct. "0,.2r",13/2

l*ugenot

isopropanol (Fig. 27.6). Most of the vanillin on the market is made this way. 3. From phenole or o-chloronitrobenzene through guaiacol, following the usual synthetic procedure.

NO,

I

tiugenol

[6)"t'' \.,-

2. From.lignin8 through an alkaline pressure cook at g00 to 1400 kPa for }6 to I h. The vanillin is puriffed through the sodium bisulfite compound and extraciion with benzene or

o-uANo. lusk

(CH.)3C\2CH, NO,

Orkl,irion Procecses. Vanillin is one of the most widely used flavors, more than ti80'000 k-g/ye* being man$factured. It is used as a flavor in perfumery and for deodorizing manuf.-cturud goods. Many processes have been employed in its manufacture. srch as the

..;"YA

From eugenol from oil of cloves, through isoeugenol, followed by oxidation to vanillin, using nitrobenzene as the oxidizing agent:'

/.?YAr

Ne',cr'o7

: :.HCH3 *# *n:'' tr:'S{)., ii-#; jffi,;!,

[:--r!2cu,cH

I

following:

l.

OH

(:.Hsto2,

I

t

-sCIil

".,Tj:,1:,,,.

CH,

It

is pro-

o-Y,A\

tq']g].r" i*,.#;

806.

,r" US. Patent 3,054,659 (1962); ECT, Sd ed., vol. 14, 1981, p. i esch*yzer, Die Fabrikation pharmazeutischer und chemischtechnischer Produkte, Springer, Berlin, 1931, pp. 205-2@.,279-288.

496

Ch.p. 27 Fllag"anccq Flavota, and lod

Addlttvct

The Perfumc

Ind.uatry

499

rernoved saccharin from the Generally Recognized as Safe (GRAS)ro list and required that all food and beverages containing saccharin have a warning label. A study was undertaken by the National Academy of Sciences to determine.its safety for human corisurirption, but it did not provide definite conclusions.ll In Ig77 the FDA restricted the use of saccharin, a decision based on limited test data on laboratory animals. Saccharin is manufactured, employing the itollowing reactions, with a 90 percent yield on the last step.

"Tik:'

.."t)'.:rll' .' .fill:i;,:lt*

Fractionariv precipitated

o Fig. 27.0. Vanillin from lignin. lChem. Week 89 (37.)

103 (1961)'l

,,.(iri.iL6H4sozcr

which tntsaldehgde is a colorless oily liquid with an agreeable odor resembling coumarin' (the of anethole oxidation the by is made It in mixtures. i, i"r"fop.a anly after dilution and recently in obtained has been Anethole oils). fennel and anise, star anise, of chief constitueni this country at very low cost from higher-boiling fractions of pine oil'

-Su

7--i

\/itt:

r",c,,o,

5

o.crtr.,r.^p rso2NH2

o-Toluene sulfochloride,60

%

o.),rH,CuH,CooH

cHo 'Anthranilic

out in the liquid Phase. VAPON PIIASD

coHscHsff"rrr"ro + Hro

,/--Y"-N,

llll

\;-srt,

o,Sulfamvlbenzoir arid

acid

*ffi oto*" -- -sorcr

fi oi Saccharin

Miscellaneous Processes, Aspartame,t2 l-aspartyl-l-phenylalanine, is 200 tim6s sweeter than sugar. It has recently won limited approval from the FDA for use in some foods, and for use in soft drinks. It now is able to compete in the nonnutritive sweetener market with saccharil, which has been on the market fqr many years.tB The regulation that requires a warning label on saccharin-containing foods will expire in 1g83, and, uniess it is'extended, aspartame will be the only accepted'nonnutritive sv/eetener on the market. Saccharin consumption is about 7 g per capita per year, and 3 to 4 x I03 tfyear is produced, so the market is large.lst A combination of saccharin and aspartame is sweeter than either compound alone and aspartame has no objectionable aftertaste as saccharin does. Aspartame, however, is not very stable to heat and liquids, but it will retain its sweet taste in soft drinks for about 6 rnontl-,s.

AH

= -382kJ

oxide gives is claimed that a catalyst mixture of 93% uranium oxide andTVo molybdenum relatively high yields.

It

LICIUII' P'IAIJE

+

C6HsCHs

\---\so?NHz

^t'

Itertaste

-Fn'V

and as an Benzaldehyda is used as a flavoring agent, as an ingredient inpharmaceutieals, and in methods several produced by is it intermediatein chemical syntheses. Commercially, in intermediate as an used grade is largely te6hnical The ieffned. and i;;;r"d"r, technical Most dyes. and aldehyde, the slynthesis of other chemicals, such as benzyl benzoate, cinnamic oiltl tu"t"i"al grade is made by direct vapor-plra_s1 oxidation-of toluene,.although someForis by alkaline oracid hydrolysis' -"a" Uy chloriniting toluene to Lenzal chloride, followed perfume and flavoring use, the reffned, chlorine-free grade is required, which is economically of toluene. 'ihis oxidation is sometimes carried iroduced by the direit vapor-phase oxidation

i*Ii' '' (Y(

idili.d h.at.,l

a,

An alternaie synthesis from an.thranilic acid is clajmed to yield a prodrrct with less bitter .r

-ry' [7-\l

cttctt.

il

:ooN3

HrO

-;*C6H5CHO Sacclnrln l)SP (o-benzosulfimide) is approximately 500 times sweeter than sugar' It has been widely used by diabetics and in diet drinks and foods. However; in 1972 the FEA

Terpineols are among the cheapest synthetics and are widely used in soap because of their *'oodsv and floral odors. Formerly, all terpineols were made from turpentine oil, which consrsts largely of a-pinene, but recently pine oil has become an important source. Terpinecils

- tHrll, CR^--toncept and Appiication, Food TechnoL

29 (t)48 (i975) rrNational Academy o[ Science Report No. PB-2381'37/AS. Ig75 lavailable from National Technical Information Service, Springfield, Va.), i2For saccharin and aspartame, Food Eng.54 (7) 77 (1982). '*Sugar Substitutes Seek Sweet Smell of Success, Chem. Eng. News 52 (44) g7

Ens.4S (8) 27 (1974). r8"t : looo kg.

(lSi4), Food

f I

T

500

TheFlavorlng,Indurt"y 501

Chap.27 trl.tr:arncar,'FlavorqtndFoodAddltlvea

pinene by reaction with sulfuric may be manufactured direetly in a one-step process from purified by fractional distillation' The is product The acetone for 6 hat 35io 40"G. ""ii intermediate, terpin hydrate' ""a the of purification the in that advantage en tru*rt"p -utt od has by reacting pinene with dilute sulis easiei than that of terpineol. ierpin hydrate is formed is dehydrated to terpineol bv oxvhydrate purified The furic acid "nd "n "*,rkil;i;;"g""i. pine oil by fractionai distillation' from separated are Tefpiieols acids. ;;;;;J;"ilxylic ' Mentholhds long been exiracted as the levo from from oil.of Japanese peppermint and pure optically ,J i; cigiarettes "id rrr"rry other products as an antiseptic cooling flavor The compound is This (from turpentine)'t4 froio. B-pinene active for-m is made by Ciidden catalytical conversion make to B-citronellal' dehydrogenated and isomerized, hydrogenated, yields l-menthol, after fractional distillation and isopulegol,

;;;r;", crystallization -''ih,

Table

Classification Straight floral Floral bouquet Aldehydic floral

"rd'hyarog"r,atioi

only slightly modified from that of aldehydes but soaps, which are very difffcult to hare great alkali re,istance. Flence these acetali are used in

o"rtol" of aldeh,ldes have an

27.3 Types of Perfumes

o-dor

Manufacturer Coty Revlon Chanel Coty Factor

Trade Name Muguet des Bois Charlie Chanel

#5

L'origon Acqu4marine

Oriental Chypre Woody

Jovan

Green

Shulton

Citrus'

Jovan

Cougere Canoe

Dana Faberge

Musk

Jovan

Musk Oil

Spice

Shulton

Old Spice

Sport Scent Old Spice Herbal Eau Fresh 20 Carats

Brut

perfume.

Perfrpfre Formulation a widely sold product (Table 27'2) acrual example of a compound perfume sin rilar to t1'ki and shows- their use in a blended discussed been haue 4it""i"r ii";r;i;;r ";ponents that and bergamot oil. Although ionone, methyl eugenols, from are oio* prJ"". TheToundatio., may contain 50

fragrance ihe formulation given in the table sho*s a 1o*er number, a single 300 ingrediertts may be as many as fact, in subcompounds; to l0O different compounds and available for perfume are oils synthetic 30oO and natural 500 appr.gimately

"r.J production.l5

do- not manufacture their F}Ail,rANCE IUALITL. The majority of domestic perfume houses custom-made by synthetics their o*n ,""rtr, they usually import natural floral oils and have

'frees, CHEMTECH 5 (4) 235 (1975)' (1960)' Fragrance-Front-Runners, Chem'Week 86 (I) 24

f'"*

"CI[Itlt 'sAerosols;

Table

otto

l0 u7.5 40

l0

l0 l5

:

Jasmine absolute

20

Eueenol (from clove oil)

90

lsolates '

San-talol

(irom sandalwood

Grams

Synthetics

Petigrain oil Orange flower oil Rose

Component

Grams

Essential gils Sandalwood oil 'Bergamot oil ., YlanS-Yl&ng ou

)

Semisvnthetics

(from eugenol) -Isoeusenol ilelioirbpin (f rom saf role) Methyl ionone (from citral)

I5

llb 15 ?,37.5

The psychological effect of odor is successfully used primarily to increase customer appeal. Perfumed merchandise outsells its odorless counterpart by a large margin. An insurance company increased its sales of fire insurance overnight by sending out advertising blotters treated to simulate the acrid odor of a fire-gutted building. All kinds of paper are now perfumed to increase sales appeal. Table 27.3 lists the main types of perfumes.

THE FLAVONING INDUSTRY

27.2 Cornposition of a Perfume Component

'

aromatic firms. As the perfumer's skill and resources increase with experience and research, new equipment is developed for identifying fragrance components, even in trace quantities, such as infrared and ultraviolet spectrographs and chromatographs. Eventually, such instrumentation'will be perfected to expedite production, but currently the perfumer's nose is regarded as the.more discriminatory in arriving at a creative blend of exotic ingredients. Even he or she does.not know precisely what will make one formulation successful where several hundred others may fail. Furthermore, after months of trial to attain certain objectives, a consumer may be unenthusiastic about the product. High quality from batch to batch is routinely ensured by standard tests, such as speciffc gravity, optical rotation, refractive index, acid number, and ester number. Provided success is met thus far, "the name, the package, the advertising must all be perfectly orchestrated" with the product.

27.5 20

Coumarin

Vanillin

30"

Benzyl acetate Oleoresin, oPoPanax Balsalns (resinoids)

2.5 5

Tolir Peru Benzoin Animal ftxative, castor tincture Synthetic fix.tives Musk ketone Musk ambrette Vehicle, ethyl alcohol

70

l: l0

12.5

32.5 12.5 450 kg

There are oniy four basic flavors which the nerve endings in the taste buds on the tongue can detect: slfeet, saur, salt1, and bitter.to The popular conception of flavor, however, involves the combination of these four basic stimuli with concurrent odor sensations. Apple,' for instance, tastes merely sour, with a trace of bitterness from the tannins present. The main concept received of an dpple is due to the odor of acetaldehyde, amyl formate, amyl acetate, and other esters present in the volatile portion. The principles of perfume blending also hold good for flavor manufacturing. The best flavoring essences are natural products altered and reinforced where necessary by synthetics. In addition to alcohol as a vehicle, glycerin and isopropyl alcohol are used for liquid preparations, dnd emulsions of bland gums, such as tragacanth and acacia (gum arabic), for pastes. The same fixatives are employed, especially vanillin and coumarin; animal types are r1sed sparingly. Many esential oils ffnd application r6Hornstein and Teranishi, The Chemistry of Flavor, Chem. Eng. News 45 (32) 9S (1967)

502,

Thefllavoilnglnduslry 503

Chap.27 Fratrances, Flavors, and Food Addillvea

in the flavor industry, the more common being spice oils, citrus oils, peppermint, and spearmint, Alpost all peqiume synthetics find acceptance, plus a number made especially for flapropionic, vors. The esters;f ethyl, methyl, arnyl, propyl, and benzyl alcohols with acetic,

for*i", valeric, and anthranilic ir" irr.ii flavors. As *ith flo*"t perfumes, many chemical

butyric, salipylic, caproic,

acids are widely used to characterspecialties keynote individual fr.it

fresh odor of a cut aromas. The 7-lactorre of undecylenic acid is a true representation of the not a peach. A strawberry base is the ethyl ester of methylphenylglycidic acid, although it is and of'anise taste the has Anethole true effect and pariakes of a sornewhat unnatural tone, pineapple licorice, benzyl acetate tastes like raspberry or cherry, and allyl caproate is used for (cinnamon), cinnamaldehyde are flavorings for used compounds common Other flavors. diacetyl (butter), menthol (mint)' and isoamyl acetate (banana)'

,Vafural Fruit Concemtrates as those used for Although the essential oils used in flavoring are the same grade and sor'rrce of the large Because different rnanner. f.rfr*""r, fruit flavors are handled in a somewhat in the strawto 90% (from the t"run, in 75% percentage of water in most common fruits matefermented easily other and sugar of amounts of considerable presence berry) and the following: rials, special processes must frequently be employed, such as the

Distillation

and.

ertraction of the fruit, The tipe fruit

is stoned and

comminuted lt

is

in a then subjected to steam distillation and rectification rintil all the aroma is concentrated petrolow-boiling with extracted portion is then This distillate. small portion of the aqueous le,r* eth.r, and the eiher re*oued under vacuum to leave an es$ence, or quintessence' of method. used. Cherry, apple, strawberry, and raspberry are.treated by this juice is extracted filtered and expressed the this system In Ertraction of the

tie fruit

iuile.

shghtly directly without previous distillation. Occasionally, the juice is allowed to ferment flavor' before extraction. This is supposed to result in a fuller Concenbation of the iitie, The expressed and filtered juice is concentrated in vacuum and the sugar evaporators with a llow i"g."" o[ heat until the water is largely driven off

of concentrate often concentration is high enough to inhibit bacterial grorrth (60%). This type An alternative method the strawberries of "1^,,," case in the especially o.'"oo.-k"d flaror, h"r, the mush of pracsufficiently, temperature the reducing Afier is freezing. of concentration juic"e and refiltered is refrozen ir.rlly pur" water ice is filtered off, antl the partly concentrated producing concenof mcthod optimum the is This until the requisite strength is obtained. can be oxidatiort from off-flavors the slight and heat, from injury is littie trates, sinceihere avoided by running the process in an atmosphere of carbon dioxide

,ANTLLA. .The vanilla bean is grown principally in Madagascar, Tahiti, and Mexico' It is the which immature fruit of the orchid Vanltli planit'olla and is cultivated as a vine on trees green to a uniform just frorn to turn starting are it. The pods are picked when they curing a pods undergo green The odqr. disagreeable rather a have and yeilo* at the tip dark-colored. irEatment of from 3 to 5 months'duration. The cured bean is pliant, shiny, and crvstals aromatic white left have may treatment The odor has become full and rich, and the present in glucovanillin, glucoside the is that happened What has the bean. on the outside of aro' the bean, has been acted upon by a ferment and split into glucose, vanillin, and other matics. Substances identifiei in the vanilla bean are anisic acid, alcohol, and aldehydel 'anillic acid and alcohol; cinnamic acid and its esters; vanillin' eth;'l vanillin' and possibly other homologs of vanillin.

Preparation o! oanill.a ei,xtract. One hundred pounds of a blend of Mexican and Bourbon finely cut up and macerated cold, with three'successive portions of 35% ethyl alcohol of 4E kg each. These extracts are combined to make a fine vanilla extract. Other solvents may f. ,sed and the extraction carried further, but the product is coarsei and less desirable as a fine flavor (cf. Fig. 27.6). beans is

CfiOCOL/ITEANDCOCOA. The cacao bean, the seed of Theobrorno cacaoL, grows in equatorial areas on the tree in podq with from 30 to 60 beans. The pods are spiit open, and the watery pulp containing the seeds is allowed to ferment in boxes from 2 to 7 days, which, in additio; to liquefying the pulp, kills the embryo (46oC), reduces the toughness of the bean, frees theobromine from the glucoside, and reduces the astringent tannin content. This fermentation is necessary for flavor in the final product. The fermented beans are dried and shipped to manufacturing centers. The beans are then heated in rotary loasters between 105 120oC, which develops the true chocolate flavor and aroma, relnoves unpleasant tannins "nJ and volatile matter (butyric and acetic acid, organic bases, and amines), dextrinizes the starch, and embrittles the husk. The roasted beans are quickly cooled to prevent overroasting, cracked in a conical mill, dehusked by a winnowing air stream, and degerminated. This product is knoq.n as cacao nibs. To work up the cacao product into chocolate, the "modern method is to grind sugar in a closed-circuit disintegratcr and the nibs in a separate water-cooled twostage disk miil with closed-circuit removal of the fines. The two are then mixed. This method p.odu"", a fine, uniform product. The paste is run through a'concher, which is a granite bed with reciprocally acting granite rollers. It reduces the particle size to an average of less than I pm. It is steam-heatedlo run at 57oC or can be allowed to heat itself by friction (50"C).

by adding condensed fresh milk or milk powder to the mill product has a cocoa-butter content of 30 to 35% and, not less than (melangeur). The finished lyVo milk solids. For cocoa, the roasted and ground beans ate subjected to pressure in hydraulic presses to remove some of the fat content. Whereas originally roasted be4ns contain SS% fat, the product remaining after this treatment has the fat reduced to20Vo, and is known as cocoa. The removal of fat makes a beverage that is not too rich and one in which the fat Milk

chocolates are prepared

does not separate on top. MONOSuDTUM GLU'.1AMATEIMSL, COOH\CHTtTCHQ|H)COONaL This compound is an impor.tant flavoring agent, yet has no flavor of its own. It accentuates the hidden flavors of food in which it is used, Reports that the use of MSG in foods is harmful were denied by a National Academy of Science-National Research Council report in 1971.17 In 1974 the Food and Agricultural Organization of the World Health Organization approved the use of MSG as

safe. Glutamic acid exists in three forms, but only the monosodiunt salt of L-glutamic acid has a- flavor-accentuating capacity. Although glutamic acid is a constitpent of all cornmon proteins, the economical sources have been wheat gluten, corn gluten, and Steffens filtrate. When Steffens beet-sugar wastes are used, the principal steps involved are (I) concentration and collection of the Steffens filtrate, (2) its hydrolysis, usually with caustic soda, (3) neutralization and acidification of the hydrolysate, (4) partial removal of the inorganic salts, and (5) crystallization, separation, and purification of'the glutamic acid. MSG is made from the acid as described above. The pr"r".,t production of MSG is largely from fermentation,r8 and a

t'Chem. Eng. Neus 49 (28) 17 (197I). rENew process es, Chem.

Reviews:

Eng. 69.(16) 17 (1962); Ind. Eng. Chem. Annual Unit Processes Hoelscher, Feimentation, chem. Eng. 7l (8) 9r

Fermentation, from 196I on;

(t964); ECT,3d ed., vol. 2, 1978, p. 410.

504

Chtp.

2E

Frryrtncoa, Nlloer., r,ed Food Addltlvcc

Fmd Addltlves

flowchart is presented inEig.2i.7, Several U.S. companies have developed their own microbiological process or obtained it frorn the ]apanese. The raw material is frequently dextrose oo rulnr. Ho*"r"r, the jlpanese are using a synthetic process based on acrylonitrile.

Fl av o r- E ssenc e F or

mulati onte

Formulas are given in Table 27.4for a fruit,flavor used in gum manufacture and a natural apricot flavor. These show how a well-balanced flavor may be made up of na,tural products reinforcbd with suitalle synthetics as well as a wholly natural formulation. Many formulas are to be found in print which consist mainly of esters of synthetic origih. These are harsh and unnatural, and, in.many cases, the only resemblance'to the original is in the designation of the flavor.

Table

27.4 Typical Flavors Artiffcial Fruit Flavor for Chewing Gum

Heliotropin Ethyl vanillin Vanillih Aldehyde

C16

Oil of cloves Oil of peppermint C)il of orarrge

Absolute carob Vanilla extr act

"The food revolution in progress since the turn of the century almost deffes description. The us-on fertile farm lands, and in lush orchards, among grazing herds

evidence is all around

reMussinan, Analytical Chemistry and Flavor Creation,

CHEMTECH i0 (I0) 618 (1980)

0.05 1.00

2.00 0.55 1.00

2.00 37.00

Oil of lemon Oil of tangerine Elhyl acetate Ethyl butyrate Isoamyl acetate Isoamyl butyrate

5.00 5.00

I6.40 r5.00 10.00

5.00

Naiural Apricot Flavor

Apricot juice conc

FOOD ADDITIVES

505

99.6 0.1 0.1

Oil of orange Oil < f petitgrain Oil bitter almond

0.1

0.05

0.05

and loaded refrigerator trucks and railroad cars, in magnificent food stores and, finally, in kitchens and on dining tables at horne or in restaurants."20 The food industry; estimated at

X IOe yearly, is the country's largest business. The average family spends approximately l8 percent of its income on food. (See chap, 25, Food and Food By-Product Proover $2(D

cessing Indr:stries, for details on the size of this industry.) Food additives are those chemicals combined with foods by the manufacturer to effect certain modiffcations involving preser-

Sugor

amfronio Olher rolids

vation, color, Ilavor enhancement, and stabilization, which have helped 1o make an astounding improvement in our food supply, as well as alleviating v.rork in the kitchen. Additives are as old as history itself, spices, for example. Intentional odd.itioes are substances added in caiefully controlled amounts to preserve the quality of food, improve its nutritive value, or add flavor, for example, MSG (Fig. 27.7). Common kitchen staples such as vinegar, starch, and salt are in this category. Incidental addltiDes are those that, although havipg no function in finished food, become part of it through some phase of production, processing, storage, or

lnoculohl

packaging. By-Ptoduct moiher liquor

oeeoiorizrr

Tolproduce

I

tj

of MSG' HrO, the following materials and utilities are required:

Sugar.

1.5-2.5 t

Fuel

46.4

MI

Electricity

79,200 MI

Direct labor

17.6

wort-h

Sig i?.7. Flowchert of

ad

Clpm. Corp.)

monocodium glutarnate ptoduction by fer,mentation. (Intenwttor,,,,l Mlnerals

The food additives have been separated into 52 categories.2r This list ranges from acidulants, anticaking (drying) agents, baking aids (yeast foods) through flavors, flavor enhancers, starch modifiers, nonnutritive sweeteners to preservatives, sequestrants (chelating agents), stabiiizers, r,itamins, and wetting agents. The main classifications22 are colors, 3 percent; flavors, l6 percent; enzymes, 8 percent; acidulants, 8 percent; nonnutritive sweeteners, 2 percent; surfactants, l0 percent; antioxidants, 3 percent; preservatives, 4 perceflt; flavor enhancers, 7 percent; vitamin supplements, 3 percent; and nonspecialty additives su'ch as soy concentrates, carrageenin, algrnates, and le.avening agents, 36 percent. Commonly used additives include chemical preservatives like propionic acid and benzoic acid; Lnffers and neutrohzing agents, such as acetic acid and sodium citrate; emuls$ging

wFood Addltloe$ Coder, 1972, Manufacturing Chemists Association; Furia, Handbok of Food Addtttoes, Chemical Rubber, Boca Raton, Fla., 1968; Fernandez, Mixing Technology and Food, Nea Eng.3 (11) 52 (197a); ECT,3d ed., vol. rI, 1980, p. 146.

ItFood Ingr,edients Dl,recton4, Intechmark Corp., Palo Alto, Calif. DAnother Checkup for Additives, Chem.Weekl2T (17) 29 (1980).

I

,,

I

506

Foorl

Ch.P.27 F"agi.nccc,flavorc,andFoodAddltlvet

egents likepolysorbates;

nonnutfitioe

iu)eeteflers , such as saceha rin;

nutfient

.$

, among

which

other vitamins; a\d thickdners like agar'agar and acacia' Here should "rd (Table 27' l) such as bitter ""id "r""rUr" "i" ; t;;il; re"^ like allspice and ginger and, ftnally, essential oils i.*on. Somelof these adJitives are permitted to be used freely, and others in

"rd "f-.ra amounts, limited t Contrary to ih" fpl is conducting an on-going review of the GRAS list of substarrces' products is not comfood in safety concerning ,"gul"iio, governniental p";;;r- ;d*"r, pt"iety bi"t"d on ihe side of the food industry'

to realize that the average is useful in gaining perspective on the use o{ food additives 63 kg are food additives Of the only that and of year, p"' food of t! p"rr* "orrr,*"Joso and dextrose which are all normal' 63 kg, 58.5 kg are compor"d of "'g'i, salt, corn syrup' the acidity for 4 kg' adjust to used .","i"f t*arl* Leavening agents Jr substances among about r80o difdivided are These additives. other of [g olr which leaves only about food and add greatly preserving ferent substances. Food Jir,ii* pl"V an invaluable role in food additive the new any For appearance' and i"'iu *.r"r, stability, flauor, abundance, documented contain (FAP) must which Petition Additive Food of a FDA requires lubmission of intended use(s), efficacy at specific levels in the food

It

into.r.,"iio., on safety,'declaration

;;"rfacturing detaiis including intermediates, and an environmental impact statejust to obtain FDA approval' ment. It has been estimated that it carieasily cost $I million have been approved in the last 20 products new a dozen than less *rt, t igt i, oiit ;;;;" years, but the FDA is currently vears. Most of the additires used have been apf.or"d for

;;;;,

"rrg"g"d

in requiring the retesting of rnany of them'

amounts NATUVAL ACCESSORY CHEMTCALS. Foodstuffs contain small

of

accessory cherr'li-

Carbohydrates i.,"i,rding vitamins (Chap: 40), chelating agents, and.natural antioxidants' Proteins are comand ""ir, (Chap. celluloses, 3b), !ums. dextrins starches, sugars, various consist of stearic acids' .i"*i"o acid"s. Shortenings contain esters of palmitic, oleic, linoieic, andsubstances p.*J -Natural that well as as value' nutritive known oI no foodstuffs contain substinces used; for example, coffee"and tea normally are than turg"i in taken if .r"-r,".-rrr ".ounts Even small amounts of arsenic contain caffeine, *hose pha'rmacological effect is well known, food' and other toxic metals are found in potatoes contain so much solanine (a deadly poiSon) that if the amount consumed by the it would be. sufficient to kill a average person in a year was concentrated into a single dose, that "natural" foods are to realize is suffilient it but horse. Thelist could be extended greatly, and safer tha"n properly prepared food containing carefullv tested

;;;";;,t;;;;

controlled additives.

"r

SELECTED REFERENCES and Flarsors, Novox' Whiting N f M. e.;rJ 6. E. Inglett: Fhoor o! Foods ond Birserages, Aeademic' New York, I97r ] W.:E. and f. A. Rogers,lr.: The Frogrance and.Flaoor Industry, Dorland, Mendham,

Aooell. L.:

Co$tttctircE, Fiagyances,

dtil"il",ud t;;d;a, 1977.

E.t

i". N. L..M: Plant

Pfgments, Flaoon and Textures, Academic, New York' 1979'

press, Boca Raton, Fla.. te75. f*iiriu iiiliurr*'iii'iiitier"itxnt'zd4.'-clc CRC Press, Boca Raton' FIa" 1973' dddtttoes, za

i'"J";

f

s. i"a;, noidfuk of F-ood

alf lt's Naturai, How

"a"

Good Is It? Food Eng.54 (3) 7 (1982)'

Addlrlves

5O7

Fleath, H. B,: Source Book of Flaoors' Avi, Westport, Conn , I98I' Heath, H, B.: Flarsor Technology, Prod.ucts and. Applications, Avi, Westport, Conn , 1978 j"lll*k, J. S.: The LIse of Fragrance in Const mer Products, Wiley-Interscience, New York, 1976. i'intrr,ro, N. D,, Food Flaooring Processes, Noyes, Park Ridge, N J , 1976' Poucher, W. A.: Perfumes, Coimetics ond Soaps, vol II, 8th ed , Wiley, New York, 1974' pruth, J. S.: Sltlces aid Condiments, ChemistrE, Mtuobiology, Technology, Academic, New York, 1980. Root, W. led.), He&s and Spices, Mccraw-Hill, New York, 1980' Telanishi, R.-and R. A. Flath (eds.): Flat.,orResearch,Rebent Adoances, Marcel Dekker, New York, ]981. Toirey, S.; Fragrances and Flavors, Noyes, Park Ridge, N'J., 198.0'