Flavor Chemistry - American Chemical Society

Chapter 14

New Dimensions in Flavor Research

Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on June 15, 2016 | http://pubs.acs.org Publication Date: February 21, 1989 | doi: 10.1021/bk-1989-0388.ch014

Herbs and Spices Braja D. Mookherjee, Richard A. Wilson, Robert W. Trenkle, Michael J. Zampino, and Keith P. Sands International Flavors and Fragrances, Research and Development, 1515 Highway 36, Union Beach, NJ 07735 Herbs and spices are not only common household food ingredients but also integral parts of various flavor and fragrance creations. Most of the spices used day-to-day are either dried or aged, but few people are aware of the fact that l i v e spices have different aroma properties from those that are dead. The chemical differences i n the aroma profiles of " l i v i n g " vs dead leafy spices have now been characterized. The methodology and analytical results for some common spices are presented. Today, i n western s o c i e t y , we take herbs and spices for granted, but t h i s was not true i n the past where they were rare and p r i z e d commodities. Herbs and spices were so precious that even a slave could be bought for a handful o f spice (1). Generally speaking, the important spices came from the East, e s p e c i a l l y from I n d i a , Ceylon, and the eastern Spice Islands. Beginning with Marco P o l o , various t r a v e l e r s l i k e Vasco da Gama ventured eastward, found the lands of s p i c e , and opened the door to the West for the spice trade. England eventually became the center for the European spice trade. I t should be mentioned i n t h i s connection that, i n the l a t e 17th Century, the Americans also benefited from the spice trade. Boston-born E l i h u Yale went to England where he worked i n the B r i t i s h East India Company which held a monopoly on a l l trade with India and whose ships brought the f i r s t cargo of cinnamon. He eventually became Governor of Madras, India and acquired a fortune which he donated to a u n i v e r s i t y i n Connecticut which now bears h i s name and i s known as Yale u n i v e r s i t y (1). From ancient times up u n t i l modern days herbs and spices have played a dynamic r o l e i n our d a i l y l i v e s . When we clean our teeth i n the e a r l y morning with toothpaste we encounter mint o i l s . When we wash our bodies and clothes with soaps and detergents we f i n d the essences o f rosemary and lavender. A t midday and i n the evening on the dinner table the smells o f spices elevate the appetite. More people than ever are discovering the secrets o f great c u i s i n e which r e l y heavily on herbs and s p i c e s . In addition 0097-6156/89/0388-0176$06.00/0 © 1989 American Chemical Society

Teranishi et al.; Flavor Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 1989.


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to the use of herbs and spices i n the c u l i n a r y a r t s , the back-tonature health movement has a l s o c a l l e d our attention t o these materials. People are buying more and more herb and spice products, however, they are not aware of the f a c t that most of these products have been processed and the aromas are e n t i r e l y d i f f e r e n t from those found i n the l i v i n g p l a n t . The reason i s that when the u m b i l i c a l cord connecting the f r u i t , flower, l e a f , or seed to the plant i s severed, these products are then e s s e n t i a l l y dead and t h e i r aroma i s perceptibly changed. The chemical differences i n the aroma p r o f i l e between l i v i n g and dead f r u i t s , flowers, herbs, and spices have now been characterized, and the methodology and a n a l y t i c a l r e s u l t s f o r several common examples w i l l now be described. The f i r s t example w i l l deal w i t h t y p i c a l r e s u l t s obtained f o r a l i v i n g vs dead flower. The f i r s t flower chosen not only has the highest p r i o r i t y i n the fragrance industry but a l s o i s h e a v i l y used f o r f l a v o r i n g foods by O r i e n t a l people. This flower i s none other than the rose which was c a l l e d the "Queen of Flowers" by the Greek poetess, Sapho, i n 600 B.C. The rose most l i k e l y o r i g i n a t e d i n China and was introduced i n t o Spain from China by invading Arabs i n the 7th Century and i n t o India i n the 10th Century (2). The rose i s p r i z e d c h i e f l y f o r i t s blossoms, and, though F t has been known since ancient times f o r the making of fragrance, i t was Empress Nurjuhan, the w i f e of Indian Emperor Jahangir, i n the 13th Century who f i r s t made a t t a r of rose by spreading rose petals on her morning bath water. Of the 200 v a r i e t i e s of rose the most coveted f o r the making of Otto of Rose f o r fragrance use i s Rosa-damascena which comes from Bulgaria. I t takes about 4000 pounds of rose t o produce one pound of Rose Otto; hence the cost of $2500 per pound. Although most roses grown f o r commercial o i l production come from Bulgaria or the south of France, i n the 1930's American h o r t i c u l t u r i s t s started t o breed hybrid tea roses f o r both t h e i r form and fragrance. Many of them have unique aromas i n t h e i r own r i g h t , although none i s the equal of Rosa damascene. One of the best from the p o i n t of view of aroma, yellow tea rose (J.F.K.), was chosen f o r a n a l y s i s . Two side-by-side experiments were performed on the yellow tea rose; f i r s t on the picked blossoms and next on the blossoms s t i l l attached to the plant. The l a t t e r i s c a l l e d the " l i v i n g flower" a n a l y s i s . (Duplicate experiments were performed on other blossoms from the same plant and on blossoms from other plants of the same species and v a r i e t y . In a l l cases, there were no s i g n i f i c a n t differences observed i n the a n a l y t i c a l data.) In the method of a n a l y s i s r o u t i n e l y employed on picked flowers, the blossoms are placed i n a f l a s k equipped with a t r a p packed with Tenax GC. The f l a s k i s purged with a i r f o r 6-12 hours depending on the type of flower, and the v o l a t i l e s are c o l l e c t e d on the Tenax and then desorbed i n t o the g a s - l i q u i d chromatograph for analysis by GC/MS. In the method of a n a l y s i s used f o r the l i v i n g flower, one s i n g l e l i v i n g blossom i s placed i n t o a s u i t a b l e glass chamber which contains a Tenax t r a p on one sidearm. A i r i s drawn over the blossom and through the Tenax trap by a pump under the same conditions as employed f o r the picked flower. In t h i s way, the aroma p r o f i l e s of many d i f f e r e n t flowers were compared.


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FLAVOR CHEMISTRY: TRENDS AND DEVELOPMENTS

The comparative headspace analysis o f l i v i n g v s picked yellow t e a rose (J.F.K.) i s shown i n Table I .


Table I . Major Differences Between L i v i n g and Picked Yellow Tea Rose (J.F.K.) Flower

Compound cis-3-Hexenyl acetate Hexyl acetate Phenyl e t h y l a l c o h o l Phenyl e t h y l acetate 3,5-Dimethoxy toluene alpha Elemene Geranyl acetone Dihydro beta i o n o l alpha Caryophyllene alpha Farnesene

L i v i n g Rose Flower % (AN) 20.7 8.4 5.7 5.5 10.0

0.3

2.2 5.8

Picked Rose Flower A i r Purged % (AN) 5.4 4.3 3.3 1.5 18.6 4.1

-2.6 2.1 3.0

These data reveal t h a t the composition o f the picked tea rose i s very much changed from that o f the l i v i n g rose. As one can see, cis-3-hexenyl acetate which c o n s t i t u t e s 21% o f the l i v i n g rose headspace v o l a t i l e s i s d r a s t i c a l l y reduced t o 5% i n the picked rose. A t the same time, 3,5-dimethoxy toluene, one o f the character-donating components o f t e a rose, i s dramatically doubled i n the picked flower, whereas important constituents l i k e phenyl e t h y l a l c o h o l and i t s acetate are reduced i n the picked flower. In t h i s way, many other common and uncommon flowers such as jasmine, narcissus, osmanthus, honeysuckle, hyacinth, l i l y - o f - t h e v a l l e y , l i l a c , and tuberose have been analyzed. I n a l l cases, considerable d i f f e r e n c e s have been observed i n the aroma p r o f i l e s of the l i v i n g and picked flowers. In connection with the l i v i n g flower a n a l y t i c a l program, the concept was a l s o extended t o the f l a v o r f i e l d , e s p e c i a l l y f r u i t s . The f r u i t s and flowers work has served as the b a s i s o f a recent report t o the 10th International Congress o f E s s e n t i a l O i l s i n Washington, D.C. i n 1986. The f i r s t subject t o be tested i n the f r u i t s area was peach due t o the importance o f i t s f l a v o r and aroma t o both the f l a v o r and fragrance industry. The peach a c t u a l l y o r i g i n a t e d i n China though botanists thought that i t came from P e r s i a , hence i t s name, Prunus p e r s i c a (Persian Plum-Tree). From China, i t s c u l t i v a t i o n spread west t o P e r s i a i n the 3rd Century B.C. eventually reaching Europe. From there, the Spanish introduced the peach t o the New World where the American Indians developed a t a s t e f o r the f r u i t , even naming one o f t h e i r t h i r t e e n months f o r i t . Thomas J e f f e r s o n , a peach l o v e r , planted peach trees a t h i s b i r t h p l a c e , M o n t i c e l l o , i n V i r g i n i a , when he became President (3). This i s a b r i e f h i s t o r y o f the peach, and now the a n a l y s i s o f the l i v i n g peach w i l l be described. A peach s t i l l attached t o the t r e e was selected f o r a n a l y s i s on the basis o f i t s possessing a f u l l , r i c h , at-the-peak-ofripeness aroma. Taking care not t o b r u i s e the f r u i t , the peach


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was placed i n t o a f l a s k which was designed t o handle larger objects. With the Tenax trap and pump i n place, the r e s p i r a t i o n gases of the f r u i t were c o l l e c t e d f o r 16 hours. A peach o f equal ripeness was harvested from the same tree and immediately s e t up for c o l l e c t i o n o f i t s v o l a t i l e s . The major differences between the headspace v o l a t i l e s o f l i v i n g and picked peach are shown i n Table I I .


Table I I .

Major Differences Between L i v i n g and Picked Peach L i v i n g Peach % (AN)

Compound Ethyl acetate , . Dimethyl d i s u l f i d e cis-3-Hexenyl acetate, . Methyl octanoate E t h y l octanoate 6 - P e n t y l a l p h a pyrone gamma D e c a l a c t o n e { a )

( a )

^

6.2 0.6 9.7 34.2 7.4 trace 2.5

Picked Peach A i r Purged % (AN)

7.1 11.0 10.6 39.2

I d e n t i f i e d f o r the f i r s t time i n peach

One can observe that the major v o l a t i l e s o f l i v i n g peach are lower b o i l i n g w i t h methyl octanoate, now i d e n t i f i e d f o r the f i r s t time i n peach, predominating. The i d e n t i f i c a t i o n o f dimethyl d i s u l f i d e f o r the f i r s t time i n peach i s o f i n t e r e s t . Very l i t t l e peach lactone and pentyl pyrone are seen i n the l i v i n g peach, whereas they are major components o f the picked f r u i t . Methyl octanoate i s considerably decreased and the lower b o i l i n g constituents are e s s e n t i a l l y gone a f t e r p i c k i n g . I t i s reasonable t o expect that what i s true f o r l i v i n g and picked f r u i t s and flowers could a l s o be true f o r herbs and spices, although i t i s possible t o keep herbs and spices i n an acceptable o l f a c t o r y condition f o r longer periods o f time than one can preserve picked f r u i t s and flowers. The f i r s t subject f o r t e s t i n g of t h i s theory was mint because of i t s extensive use i n the f l a v o r industry. American spearmint, Mentha s p i c a t a , w i l l be described f i r s t . I t i s i n t e r e s t i n g t o note that the word "mint" was coined by the e a r l y Greeks a f t e r the mythical character ΜΙΝΓΗΕ. The term "mint" r e f e r s t o the d r i e d l e a f o f the spearmint p l a n t , which, a v a i l a b l e i n f l a k e or e x t r a c t form, has an aromatic, sweet f l a v o r with c o o l a f t e r t a s t e (4). I n t e r e s t i n g l y , American spearmint i s not native t o North America but was introduced from Europe during the 17th Century and has since been widely grown. M i l l i o n s o f pounds o f t h i s o i l have been produced i n t h i s country due t o i t s extensive and popular use as a f l a v o r i n g ingredient, p a r t i c u l a r l y i n chewing gums and toothpastes. The technique o f headspace analysis of the l i v i n g and picked American spearmint plant i s the same as i n the case o f l i v i n g and picked flowers and f r u i t s . The picked spearmint was taken from the same p l a n t used f o r the l i v i n g plant a n a l y s i s . I n order t o


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simulate the commercial process f o r making spearmint o i l freshly picked stems and leaves were kept at room temperature f o r 24 hours with a weight l o s s o f 50%. This semi-dried material was then analyzed f o r headspace v o l a t i l e s and compared with that of l i v i n g p l a n t s . Table I I I represents the comparative analysis o f l i v i n g vs picked spearmint plant and, f o r purposes o f comparison, a t y p i c a l commercial o i l . f


Table I I I .

Major Differences i n Spearmint V o l a t i l e s L i v i n g Plant % (AN)

Commercial Hexanal Hexanol Limonene Dihydro carvone Carvone Menthone/isomenthone Menthol isomers 1,3,5-Undecatriene (mixture of 4 isomers)

( a )

0.5

17.7 0.7 24.0

0.5

Picked Plant A i r Purged % (AN) trace 2.3 1.8 2.6 70.0

-

-

Comm. Oil

-0.1 21.4 0.1 63.0 1.2 1.7

-

* ' I d e n t i f i e d f o r the f i r s t time i n spearmint v o l a t i l e s I n t e r e s t i n g l y , neither the isomeric menthones nor the isomeric menthols were detected i n the l i v i n g o r picked p l a n t m a t e r i a l , but they are both present i n appreciable amounts i n commercial o i l . A t the same time, a very powerful green odorous compound, 1,3,5-undecatriene (isomer mix), has now been i d e n t i f i e d for the f i r s t time i n the l i v i n g spearmint t o the extent of 0.5%. One can a l s o observe that carvone, the true character-donating component of spearmint o i l , constitutes 70% of the t o t a l headspace v o l a t i l e s of picked spearmint but only 24% o f those of the l i v i n g plant. The opposite i s true i n the case of limonene which i s only a minor constituent i n the picked plant but a major component o f the l i v i n g mint. These v a r i a t i o n s i n constituents will d r a s t i c a l l y influence the odor of l i v i n g spearmint. A f t e r spearmint, n a t u r a l l y comes peppermint, Mentha p i p e r i t a , as distinguished from the many other species o f Mentha herb including Mentha s p i c a t a . This herb i s native t o Europe and has become naturalized i n North America. Of the many hybrids o f peppermint, only two v a r i e t i e s , black and white, a r e commonly grown. Of these, black peppermint, a l s o known as E n g l i s h peppermint, i s the v a r i e t y most extensively grown i n the United States because o f i t s hardiness and high o i l y i e l d . The United States i s the world's l a r g e s t peppermint o i l producer, and the o i l i s mainly and extensively used f o r o r a l hygiene products, chewing gum and confectioneries. Pure peppermint o i l has a very agreeable odor and a powerful, aromatic taste followed by a sensation o f c o l d when a i r i s drawn i n t o the mouth (5). Table IV represents the comparative analysis of l i v i n g vs picked peppermint plant and commercial o i l . These experiments were performed on black peppermint.


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Table IV. Comparative Analysis of Peppermint V o l a t i l e s


Compound (a) Hexanal cis-3-Hexenal trans-2-Hexenal (a) cis-3-Hexenol (a) trans-2-Hexenol (a) Hexanol (a) 2,4-Hexadienal (a) l-0cten-3-ol Eucalyptol Menthone isoMenthone Menthofuran neoMenthol Menthol neoisoMenthol isoMenthol Pulegone 1 3 5-Undecatriene (a) (mixture of 4 isomers) r

(a)

r

L i v i n g Plant % (AN) _

0.2 9.6 49.7

-1.6

trace

0.6

Picked Plant A i r Purged % (AN) 0.1 0.5 0.8 0.3 1.4 0.5 0.1 2.0

-

12.7 7.7 26.3

4.7 24.5 -

Comm. Oil

-5.7 18.1 2.3 5.2 1.7 44.2 1.9 0.2 1.7

I d e n t i f i e d f o r the f i r s t time i n peppermint v o l a t i l e s

As one could see, tremendous differences e x i s t between the l i v i n g and picked peppermint v o l a t i l e s . For example, six-carbon alcohols and aldehydes are present only i n the picked plant. I n t e r e s t i n g l y , these very green compounds have not been i d e n t i f i e d before i n peppermint. At the same time, l-octen-3-ol, which possesses an earthy, mushroom odor and which has not been previously found i n peppermint, was i d e n t i f i e d only i n the picked herb. In the c l a s s of compounds responsible f o r the c o o l i n g e f f e c t of peppermint o i l , s u r p r i s i n g l y , menthone i s a major component i n the picked herb but i s only present i n trace q u a n t i t i e s i n the l i v i n g p l a n t , whereas isomenthone, the more powerful of the two isomers, i s present to approximately the same extent i n both. Menthofuran, which has the reputation of being a less desirable component o f mint o i l s , s u r p r i s i n g l y c o n s t i t u t e s 50% of the v o l a t i l e s of the l i v i n g plant decreasing t o 26% i n the picked plant m a t e r i a l . In the opinion of the present authors, menthofuran imparts a c h a r a c t e r i s t i c fresh mintiness. On the other hand, menthol, the c l a s s i c a l cooling compound, i s present i n n e g l i g i b l e amounts i n the l i v i n g plant while i t s content v a r i e s from 5-45% i n picked and commercial o i l s r e s p e c t i v e l y . Pulegone, another c h a r a c t e r i s t i c component with a sweet, weedy, minty odor, i s a major component only i n the picked peppermint. F i n a l l y , as with spearmint, the powerful, d i f f u s i v e herbaceous - green compound, 1,3,5-undecatriene (isomer mix), was detected only i n the l i v i n g peppermint and a t a r e l a t i v e l y high l e v e l (0.6%) considering i t s strength. This compound has never before been i d e n t i f i e d i n peppermint. Now, one can e a s i l y see that a l i v i n g



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peppermint l e a f has q u i t e a d i f f e r e n t aroma from that o f d r i e d peppermint or commercial peppermint o i l . The next herb which was analyzed was rosemary, Rosmarinus o f f i c i n a l i s , not because the herb f i n d s extensive use as a seasoning, condiment, o r meat f l a v o r , which i t does, but because i t i s widely employed i n fragrancing colognes, t o i l e t waters and household products such as soaps and detergents. Rosemary i s r i c h i n legend and t r a d i t i o n . I t i s s a i d t o have been used as e a r l y as 5000 B.C. One legend claims that rosemary w i l l grow only i n the gardens o f the righteous (6). Even i n Shakespeare's "Hamlet", Ophelia s a i d , "There i s rosemary; that's f o r remembrance." I n England t o t h i s day rosemary i s placed on the graves of heroes so that t h e i r memories w i l l be e t e r n a l . I t s name i s derived from "ros maris" which means "sea-dew" (2) ι and i t indeed grows near the sea i n Spain, Dalmatia, Morocco, T u n i s i a , and Turkey. Table V shows the comparative a n a l y s i s o f the headspace o f l i v i n g and picked rosemary and a t y p i c a l commercial o i l . Table V.

Comparative Analysis o f the V o l a t i l e s o f Rosemary

Compound (a) trans-2-Hexenal (a) cis-3-Hexenol (a) Hexanol alpha Pinene Myrcene beta Pinene para Cymene Limonene Eucalyptol Linalool Camphor (a) Estragole (a) cis-Carveol (a) Citronellol alpha Campholenic a l c o h o l and acetate (a) (a)

L i v i n g Plant % (AN)

1.1 9.5 0.2 19.8 14.1 2.0 7.1 0.2 3.0 0.2 0.6 0.3

Picked Plant A i r Purged % (AN) 0.2 0.7 0.3 0.7 11.1 0.1 13.7 14.3 0.7 7.6 0.3 0.6 1.1 0.8

Comm. Oil

13.3 1.7 7.6 1.7 1.0 44.5 0.8 10.1 trace

I d e n t i f i e d f o r the f i r s t time i n rosemary v o l a t i l e s

Again, one could e a s i l y see the q u a l i t a t i v e and quantitative differences between the l i v i n g and picked rosemary. It i s i n t e r e s t i n g t o observe that the very fatty-green components, trans-2-hexenal, cis-3-hexenol, and hexanol, are present only i n the picked plant and were not detected i n the l i v i n g herb. A t the same time, hydrocarbon constituents, alpha pinene, myrcene, beta pinene, para cymene, and limonene, do not vary much from l i v i n g t o picked. However, the most i n t e r e s t i n g observation from our experiment i s that eucalyptol and camphor, which t r a d i t i o n a l l y are the major constituents o f commercial rosemary o i l as shown here, (45 and 10% r e s p e c t i v e l y ) , are present i n both l i v i n g and picked rosemary only i n very small q u a n t i t i e s , 0.7-2% f o r eucalyptol and



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0.2% f o r camphor which was not found i n the picked plant a t a l l . The present authors are, therefore, o f the opinion that eucalyptol and camphor do not play major r o l e s i n producing the f r e s h rosemary odor whereas estragole, a newly reported rosemary constituent possessing a powerful sweet, herbaceous aroma, probably i s i n large p a r t responsible f o r the fresh herbaceous rosemary character. I t i s a l s o o f i n t e r e s t t o note the i d e n t i f i c a t i o n f o r the f i r s t time i n rosemary o f c i s - c a r v e o l , c i t r o n e l l o l , and alpha campholenic a l c o h o l and i t s acetate and t o observe that the q u a n t i t i e s o f each increase on p i c k i n g . The next herb chosen f o r analysis was thyme, Thymus v u l g a r i s , which i s a l s o native t o southern Europe and the Mediterranean and i s c u l t i v a t e d i n the southern united States as w e l l . Thyme i s used extensively i n f l a v o r s f o r food products such as sauces, dressings, p i c k l e s , and canned meats as w e l l as i n pharmaceutical preparations. The e x c e l l e n t germicidal properties o f the phenols of the o i l are exploited i n o r a l hygiene products such as gargles and mouthwashes and i n numerous d i s i n f e c t a n t s . Cough syrups and lozenges are often activated with thyme o i l . I n perfumery, i t f i n d s use i n soaps and. detergents f o r i t s freshness with h i n t s o f medicinal notes. Table VI shows the comparative analysis o f the headspace v o l a t i l e s o f thyme. Table VI.

Comparative Analysis o f the V o l a t i l e s o f Thymus vulgaris L i v i n g Plant % (AN)

Compound trans-2-Hexenal 2,4-Hexadienal | cis-3-Hexenyl a c e t a t e ^ ' l-Octen-3-ol para Cymene Limonene Thymol methyl ether Carvacrol methyl ether Thymol Carvacrol (a

(a)

_

-

11.2 8.2 30.0 1.3

-

15.2 1.5

Picked P l a n t A i r Purged % (AN) 2.8 0.1 0.1 8.0 50.0 1.1 1.3 1.5 9.0 0.9

Comm. Oil

30.0 1.7

-

0.1 39.7 1.0

I d e n t i f i e d f o r the f i r s t time i n thyme v o l a t i l e s

As has been observed i n the case o f peppermint and rosemary, fatty-green six-carbon components l i k e trans-2-hexenal and 2,4hexadienal are again found only i n the picked thyme and are not detected a t a l l i n the l i v i n g plant. I t may be concluded that these components are a c t u a l l y formed by enzymatic oxidation during the overnight drying process. The fresh herbaceous q u a l i t y o f the l i v i n g p l a n t i s probably not associated with these components, but i s , a t l e a s t i n p a r t , due t o the true green aroma o f compounds l i k e cis-3-hexenyl acetate which occurs t o the extent o f 11% i n the l i v i n g plant but i s only a trace component o f the picked herb. At the same time, the c h a r a c t e r i s t i c aroma components of thyme o i l , thymol and c a r v a c r o l , are both present t o a greater extent i n



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the l i v i n g herb. I n t e r e s t i n g l y , the corresponding methyl ethers are detected only a f t e r p i c k i n g . However, para-cymene increases from 30-50% on p i c k i n g . Evergreen Cassia, Cinnamomum c a s s i a a l s o known as Chinese Cinnamon, i s native t o China, Burma, and many sub-tropical countries. I t has a long, shiny l e a f , a small pale green flower, and a loose peeling bark. The trees are grown i n plantations and are coppiced f o r the new long shoots which provide the scented bark. The stripped bark c u r l s i n t o q u i l l s as i t d r i e s and i s exported i n bundles. The d r i e d unripe f r u i t s are sold as Chinese c a s s i a buds, and the d r i e d leaves and stems are used t o d i s t i l l cassia o i l . T o t a l l y d r i e d leaves are used as a f l a v o r i n g "Tej Pat" i n the day-to-day Indian cookery. Cassia has been used as a spice i n Europe since the Middle Ages and i t has a l s o found use i n the treatment of i n d i g e s t i o n and to increase the flow of mother's milk (8). We chose to compare the v o l a t i l e s o f fresh leaves and aged leaves d r i e d t o 50% weight along with commercial o i l . The r e s u l t s f o r c a s s i a leaves f r e s h l y harvested i n Hawaii are shown i n Table V I I . Table V I I .

Compound

Comparative Analysis of V o l a t i l e s of Cassia Leaf Fresh Leaf % (AN)

(a) trans-2-Hexenal Phenyl e t h y l alcohol trans-Cinnamaldehyde Cinnamyl alcohol Coumarin 2-Methoxy cinnamaldehyde 4-Methoxy cinnamaldehyde (a)

4.0 2.1 50.0 20.6 7.9 1.0 4.1

Aged Leaf A i r Purged % (AN) 0.8 0.1 70.0 0.3 4.4 1.4 12.3

Comm. Oil _

0.4 70.0 0.3 1.7 11.5

-

I d e n t i f i e d f o r the f i r s t time i n c a s s i a v o l a t i l e s Table V I I I shows the dramatic differences between fresh and d r i e d leaves. I n t h i s case, as opposed t o peppermint, rosemary and thyme, trans-2-hexenal i s more i n the fresh than i n the d r i e d and aged. The same i s true f o r phenyl e t h y l a l c o h o l . I n t e r e s t i n g l y , trans-cinnamic aldehyde co n s t i t u t e s 50% o f the t o t a l l i v i n g headspace v o l a t i l e s , but i t i s s t i l l l e s s than i n the aged l e a f and commercial o i l . However, cinnamyl alcohol represents 20% o f the fresh v o l a t i l e s but i s only a trace component of the aged l e a f and o i l . 4-Methoxy cinnamic aldehyde, i d e n t i f i e d as a c a s s i a constituent f o r the f i r s t time, a l s o increases 3-fold on drying but has disappeared completely i n the commercial o i l . 2-Methoxy cinnamic aldehyde, sometimes c a l l e d the character impact component o f c a s s i a o i l , i s present i n the headspace o f the leaves t o only a minor extent but i t i s the second most abundant component of the o i l . An herbal p l a n t , a part o f which i s a l s o considered as a spi ce, i s the l a s t subject t o be described. This plant i s coriander, Coriandrum sativum. Even though the name, "coriander" o r i g i n a t e s from the Greek "koriannon" meaning "bug", a reference



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MOOKHERJEE ET AL.


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to the smell of the leaves and unripe seed, a c t u a l l y i t has been c u l t i v a t e d f o r thousands of years i n India, China and Egypt (S). Even today the seeds and leaves are used d a i l y i n O r i e n t a l countries f o r f l a v o r i n g cooking. But, a t the same time, o i l derived from d r i e d seeds i s an important ingredient i n modern perfumery, p a r t i c u l a r l y i n f i n e fragrances such as "Drakkar N o i r " . Since, i n the opinion of the present authors and contrary to the observations of the ancient Greeks, green coriander leaves and seeds have a very a e s t h e t i c aroma, the odor p r o f i l e s of both l i v i n g and dead leaves and seeds were compared. The data f o r coriander l e a f v o l a t i l e s are shown i n Table V I I I . Table V I I I .

Comparative Analysis of V o l a t i l e s of Coriander Leaves

Compound (a) Hexanal (a) trans-2-Hexenal (a) Hexanol (a) Nonane Decanal (a) trans-2-Decena1 (a) trans-2-Decenol (a) Decanol Undecanal (a) 2,4-Decadienal Dodecanal (a) trans-2-Dodecenal (a) trans-2-Dodecenol Tetradecanal trans-2-Tetradecenal (a)

L i v i n g Leaf % (AN) 0.4 0.3

-

15.2 11.4 35.5 2.6 2.5 1.5 0.1 1.2 9.7 0.4 0.1 3.7

Picked Leaf A i r Purged % (AN) 2.0 3.2 1.1 4.7 4.7 39.2

4.3 4.2

Comm. Herb Oil trace

-

trace 3.6 14.8 26.8 2.4 1.3 0.7

-0.5 2.7 trace trace trace

I d e n t i f i e d f o r the f i r s t time i n coriander l e a f v o l a t i l e s

As i n the case of peppermint, rosemary, and thyme, the content of six-carbon aldehydes and alcohols increases on p i c k i n g and drying. I n t e r e s t i n g l y , a very common hydrocarbon, nonane, has been found f o r the f i r s t time i n coriander i n a high concentration (15%) i n the l i v i n g leaves. I h i s compound i s d r a s t i c a l l y reduced on p i c k i n g . S u r p r i s i n g l y , nonane possesses a very c h a r a c t e r i s t i c fresh coriander l e a f odor. The decanal content a l s o decreases on p i c k i n g and aging. Decanal i s a very orangy chemical and, indeed, i t i s a character-donating component of orange o i l and, thus, lends a c i t r u s note to the l i v i n g herb. Contrary to a l l l i t e r a t u r e reports on coriander l e a f v o l a t i l e s , the major constituent reported here f o r the f i r s t time i s trans-2-decenal, the content of which i s r e l a t i v e l y constant from l i v i n g l e a f t o picked t o commercial herb o i l . Two other alpha, beta unsaturated aldehydes, trans-2-dodecenal and trans-2tetradecenal, both reported a l s o f o r the f i r s t time, are present i n appreciable q u a n t i t i e s i n both the l i v i n g and d r i e d l e a f and a t lower l e v e l s i n the o i l . A large number of r e l a t e d aldehydes and alcohols, both saturated and unsaturated, many reported f o r the


186


f i r s t time i n coriander, were i d e n t i f i e d i n the l i v i n g l e a f and i n the o i l but were not found on drying of the l e a f . The headspace v o l a t i l e s o f both l i v i n g green coriander seed and picked, d r i e d green seed were analyzed as w e l l as commercial seed o i l . Even though green coriander seed has quite a d i f f e r e n t odor from the o i l obtained from r i p e seed, these aroma p r o f i l e s are presented i n Table IX f o r the purpose of comparison.


Table IX. Comparative Analysis of the V o l a t i l e s of Coriander Seed Living Green Seed % (AN)

Compound alpha Pinene Linalool Camphor 3-Decenal ) ( Decanal J( trans-2-Decenal J trans-2-Decenol ) \ trans-2-Undecenal ) \ trans-2-Dodecenal J| trans-2-Tetradecenal * ' Geranyl acetate a

a

a)

a

a

a

a

(a)

0.1 20.9 0.3 0.4 3.1 24.9 3.8 3.7 16.7 3.8 10.0

Picked Dried Green Seed % (AN)

Comm. Seed Oil

0.3 67.1 -

5.1 73.3 4.8

0.1

12.5

2.2

I d e n t i f i e d f o r the f i r s t time i n coriander seed v o l a t i l e s

As reported i n the l i t e r a t u r e , l i n a l o o l constitutes twot h i r d s of coriander seed o i l v o l a t i l e s . On the other hand, i t i s only 21% i n the l i v i n g green seed. A t the same time, i t i s d r a s t i c a l l y increased t o 67% on p i c k i n g and drying o f the seed. Geranyl acetate, which i s one o f the character impact components of coriander seed o i l , i s present t o the extent o f 10% i n t h e l i v i n g seed v o l a t i l e s but i s reduced t o 2% i n the commercial o i l . I t i s obvious from the table that unsaturated aldehydes and alcohols are major constituents o f the l i v i n g green seed, but these compounds completely disappear a f t e r p i c k i n g and a l s o a r e absent i n the commercial o i l . I n the opinion o f the present authors, the unsaturated compounds shown i n Table IX, which have not been reported before as constituents o f coriander, a r e the character donating components o f the green seed. They a r e , undoubtedly, j u s t i f i c a t i o n f o r the Greek word "koriannon" f o r "bug". I t has been demonstrated and proved by ample examples from flowers, f r u i t s , herbs and spices that the v o l a t i l e constituents of l i v i n g natural products d i f f e r considerably from those o f the corresponding picked e n t i t i e s , j u s t i f y i n g the assertion that the odor i s completely d i f f e r e n t on p i c k i n g . To our knowledge, t h i s s c i e n t i f i c observation has never been made before. With these data, i n IFF we a r e c r e a t i n g new true-to-nature f l a v o r and fragrance compositions.


14. MOOKHERJEE ET AL.


Literature Cited


1.

Collins, M. Spices of the World Cookbook by McCormick; Penguin Books: New York, N.Y., 1964; p 4. 2. Encyclopedia Britannica, 1968; Vol. 19, p 621. 3. Panati, C. Browsers Book of Beginnings; Houghton Miflin Co.: Boston, Mass., 1984; p 105. 4. Collins, M. Spices of the World Cookbook by McCormick; Penguin Books: New York, N.Y., 1964; p 34. 5. Encyclopedia Britannica, 1968; Vol. 17, p 587. 6. Collins, M. Spices of the World Cookbook by McCormick; Penguin Books: New York, N.Y., 1964; p 50. 7. Jesse, J. Perfume Album; Robert E. Krieger Publishing Co.: Huntington, N.Y., 1951; p 83. 8. Garland, S. The Herb and Spice Book; Francis Lincoln Publishers Limited: London, England, 1979; p 48. RECEIVED October 25, 1988


Flavor Chemistry - American Chemical Society

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