Chapter 15
Peptides as Flavor Precursors in Model Maillard Reactions 1
1
1
2
Chi-Tang Ho , Yu-Chiang Oh , Yuangang Zhang, and Chi-Kuen Shu
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1
Department of Food Science, Rutgers University—The State University of New Jersey, New Brunswick, NJ 08903 Bowman Gray Technical Center, R. J. Reynolds Tobacco Company, Winston-Salem, NC 27102 2
Equimolar aqueous solutions of glycine, diglycine, triglycine and tetraglycine were heated separately with Dglucose at 180°C at pH 4-5 in a Hoke sample cylinder for 2 hr. The Maillard reactions of glucose with glycine and triglycine produced a significantly greater amount of pyrazines than either diglycine or tetraglycine. The similarity of the results of glycine with triglycine and diglycine with tetraglycine in the pyrazine formation also suggests that tripeptides or tetrapeptides could be degraded through diketopiperazines. Alkyl 2(1H)-pyrazinones were identified as peptidespecific Maillard reaction products. The volatile products generated from the Maillard reaction of glucose with glutathione and its constituent amino acids in an aqueous medium were also compared.
The M a i l l a r d r e a c t i o n i s a well-known r e a c t i o n t h a t o c c u r s i n food during cooking. Because o f t h e c o m p l e x i t i e s o f t h e M a i l l a r d r e a c t i o n , many i n v e s t i g a t i o n s have been aimed a t u n d e r s t a n d i n g the mechanisms o f t h e r e a c t i o n . The pathways f o r t h e M a i l l a r d r e a c t i o n o r g i n a l l y proposed by Hodge ( 1) have g a i n e d wide a c c e p t a n c e . Recent works on t h e g e n e r a t i o n o f aroma compounds from the M a i l l a r d r e a c t i o n were m o s t l y concerned w i t h model systems u s i n g amino a c i d s . Some o f t h e amino a c i d s used i n model systems were p r o l i n e ( 2 - 5 ) , h y d r o x y p r o l i n e (6), s e r i n e and t h r e o n i n e ( 7 ) , c y s t e i n e (8-9), l e u c i n e (10) and g l y c i n e (11-12). A l t h o u g h a wide range o f p e p t i d e s has been r e p o r t e d i n c o n s i d e r a b l e q u a n t i t y i n many food systems such as aged sake (13), meat (14) and h y d r o l y z e d v e g e t a b l e p r o t e i n (15), t h e r o l e o f p e p t i d e s as p r e c u r s o r s i n t h e g e n e r a t i o n o f f l a v o r compounds has n o t been i n v e s t i g a t e d t o an a p p r e c i a b l e e x t e n t . Chuyen e t a l . (16) s t u d i e d the r e a c t i o n o f v a r i o u s d e p e p t i d e s w i t h g l y o x a l and r e p o r t e d t h e i d e n t i f i c a t i o n o f 2 - ( 3 - a l k y l - 2 ' - o x o p y r a z i n - 1 ) a l k y l a c i d s as major 1
1
0097-6156/92/0490-0193S06.00/0 © 1992 American Chemical Society
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
194
FLAVOR
PRECURSORS
products. Most r e c e n t l y , R i z z i (17) r e p o r t e d t h a t model M a i l l a r d r e a c t i o n s o f d i p e p t i d e s and t r i p e p t i d e s w i t h f r u c t o s e g e n e r a t e d S t r e c k e r d e g r a d a t i o n p r o d u c t s , such as S t r e c k e r aldehydes and a l k y l p y r a z i n e s , from amino a c i d s w i t h b l o c k e d amino and c a r b o x y l f u n c tionalities .
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V o l a t i l e Compounds Formed from M a i l l a r d Reaction of Glucose with Gly, Gly-Gly, Gly-Gly-Gly and Gly-Gly-Gly-Gly E q u i m o l a r aqueous s o l u t i o n s o f g l y c i n e , d i g l y c i n e , t r i g l y c i n e and t e t r a g l y c i n e were heated s e p a r a t e l y w i t h D - g l u c o s e a t 180°C a t pH 4-5 i n a P a r r bomb f o r 2 h r . Each r e a c t i o n m i x t u r e was a d j u s t e d t o pH > 12 w i t h NaOH, then e x t r a c t e d w i t h methylene c h l o r i d e , c o n t a i n i n g an i n t e r n a l s t a n d a r d , i n a s e p a r a t o r y f u n n e l by m u l t i p l e ext r a c t i o n method (5X50 m l ) . The methylene c h l o r i d e e x t r a c t s were d r i e d o v e r anhydrous sodium s u l f a t e and c o n c e n t r a t e d by b l o w i n g w i t h n i t r o g e n gas t o a f i n a l volume o f 0.2 mL. The v o l a t i l e compounds were then a n a l y z e d by gas chromatography and gas chromatography-mass s p e c t r o m e t r y as d e s c r i b e d p r e v i o u s l y (18). T a b l e I l i s t s t h e v o l a t i l e compounds g e n e r a t e d i n these systems. From t h e q u a n t i t a t i v e d a t a , i t was o b s e r v e d t h a t g l y c i n e o r t r i g l y c i n e g e n e r a t e d a l a r g e r amount o f a l k y l p y r a z i n e s than e i t h e r d i g l y cine or t e t r a g l y c i n e . I t i s a l s o i n t e r e s t i n g t o note t h a t f u r f u r a l and 5-(hydroxym e t h y l ) f u r f u r a l were produced i n a g r e a t e r q u a n t i t y i n the r e a c t i o n o f d i g l y c i n e and t e t r a g l y c i n e w i t h g l u c o s e , as compared t o the g l y cine or t r i g l y c i n e . 2 - A c e t y l p y r r o l e and 2 - f o r m y l - 5 - m e t h y l - p y r r o l e were i d e n t i f i e d as t r a c e components i n t h e s e model r e a c t i o n s . The f o r m a t i o n o f d i k e t o p i p e r a z i n e s from the t h e r m a l d e g r a d a t i o n o f d r i e d p o l y g l y c i n e has been r e p o r t e d by Hayase e t a l . (19). From T a b l e I , t h e r e l a t i v e abundance o f p y r a z i n e s formed from g l y c i n e and t r i g l y c i n e are very close. However, the amount o f p y r a z i n e s formed from d i g l y c i n e o r t e t r a g l y c i n e was c o n s i d e r a b l y l e s s as compared t o either glycine or t r i g l y c i n e . The t r i g l y c i n e c o u l d be degraded i n t o g l y c i n e and d i g l y c i n e through d i k e t o p i p e r a z i n e . W h i l e t e t r a g l y c i n e was degraded p r i m a r i l y i n t o d i g l y c i n e , f u r t h e r d e g r a d a t i o n o f d i g l y c i n e i n t o g l y c i n e c o u l d r e q u i r e more energy. On t h e o t h e r hand, t h e d e g r a d a t i o n o f p e p t i d e s by d i r e c t h y d r o l y s i s w i t h o u t t h e i n t e r m e d i ate f o r m a t i o n o f d i k e t o p i p e r a z i n e cannot be r u l e d o u t . The r e a c t i v i t y o r d e r , t e t r a g l y c i n e > t r i g l y c i n e > d i g l y c i n e > g l y c i n e f o r t h e c o l o r f o r m a t i o n i n the browning r e a c t i o n r e p o r t e d by Chuyen e t a l . (16) d i f f e r s from o u r o b s e r v a t i o n f o r p y r a z i n e formation. T h i s c l e a r l y i n d i c a t e s t h a t f o r the M a i l l a r d r e a c t i o n t h e m e l a n o i d i n f o r m a t i o n i s d i f f e r e n t from aroma f o r m a t i o n i n mechanism and r e a c t i v i t y .
Pyrazinones as Peptide-specific M a i l l a r d Reaction Products As shown i n T a b l e I , t h r e e n o v e l p y r a z i n o n e s were i d e n t i f i e d i n the r e a c t i o n o f g l u c o s e w i t h d i g l y c i n e , t r i g l y c i n e o r t e t r a g l y c i n e . The p y r a z i n o n e s i d e n t i f i e d were 1 , 6 - d i m e t h y l - 2 ( 1 H ) - p y r a z i n o n e , 1,5-dimethyl-2(1H)-pyrazinone and 1 , 5 , 6 - t r i m e t h y l - 2 ( 1 H ) - p y r a z i n o n e . The mass spectrum o f 1 , 6 - d i m e t h y l - 2 ( 1 H ) - p y r a z i n o n e i s shown i n F i g u r e 1.
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
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15. HO ET A L
Peptides as Flavor Precursors in Model Maillard Reactions 195
T a b l e I . Amount o f V o l a t i l e Compounds G e n e r a t e d by G l y c i n e , D i g l y c i n e , T r i g l y c i n e and T e t r a g l y c i n e w i t h G l u c o s e a t 180°C f o r 2 Hours ik Compounds pyrazine methylpyrazine furfural 2,5-dimethylpyrazine 2,6-dimethylpyrazine trimethylpyrazine 2-acetylpyrrole tetramethy1pyrazine 5-(hydroxylmethyl)furfural 1,6-dimethyl2(lH)-pyrazinone 1,5-dimethyl2(1H)-pyrazinone 1,5,6-trimethyl2(lH)-pyrazinone a
*
a
Gly
di-Gly
tri-Gly
tetra-Gly
mg/mole amino compound 738 798 808 887
12.18 257.80 14.14 360.86
894
198.76
980
486.77
1058 1065
1.36 71.44
1208
125.61
100.44
-
-
186.81 3.87 266.57
3.17 16.93 46.88
-
139.50
17.41
8.11
375.98
54.52
10.28
797.04
1315
-
1379
-
t
1476
-
t
323.00
-
1.59 55.63
127.41
119.35
422.35
1.37
t
2.85
Linear retention indices calculated according (1974) on an HP-1 column. t = trace
to M a j l a t
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
0.57
et a l .
FLAVOR PRECURSORS
196
The s t r u c t u r e o f the p y r a z i n o n e s were c o n f i r m e d by comparing t h e i r mass s p e c t r a and GC r e t e n t i o n times w i t h the a u t h e n t i c com pounds s y n t h e s i z e d by the r e a c t i o n o f d i g l y c i n e w i t h p y r u v a l d e h y d e . These t h r e e p y r a z i n o n e s were formed by the r e a c t i o n o f d i g l y c i n e w i t h p y r u v a l d e h y d e i n y i e l d s o f 25.56%, 9.39% and 20.16% f o r 1 , 6 - d i methyl-2(1H)-pyrazinone, 1,5-dimethyl-2(1H)-pyrazinone and 1,5,6trimethyl-2(1H)-pyrazinone, respectively. The t o t a l p y r a z i n o n e s amounted t o 55.11%. A c c o r d i n g t o the mechanism proposed by Chuyen et a l . (16), v a r i o u s d i p e p t i d e s would r e a c t w i t h α-dicarbonyl com pounds t o y i e l d the p y r a z i n o n e d e r i v a t i v e s , 2 - ( 3 ' - a l k y l - 2 - o x o p y r a z i n - 1 - y D a l k y l a c i d s . On t h e o t h e r hand, t h e d e g r a d a t i o n o f g l u c o s e would produce v a r i o u s α-dicarbonyl compounds such as g l y o x a l , py r u v a l d e h y d e and d i a c e t y l . As shown i n F i g u r e 2, i n the case o f py r u v a l d e h y d e , t h e amino end o f t h e d i p e p t i d e would p r e f e r t o r e a c t w i t h t h e a l d e h y d i c c a r b o n y l group than t h e o t h e r ketone c a r b o n y l carbon because o f a s t e r i c e f f e c t . A f t e r Amadori rearrangement, t h e i n t e r m e d i a t e o f d i p e p t i d e - p y r u v a l d e h y d e was c y c l i s i z e d t o form 2( 3 - a l k y l - 2 - o x o p y r a z i n - 1 ' - y D a l k y l a c i d s . A t t h e e l e v a t e d tempera t u r e (180°C) used i n o u r model experiment, t h e 2-(3 alkyl-2'-oxo p y r a z i n - 1 - y D a l k y l a c i d s would undergo d e c a r b o x y l a t i o n t o y i e l d 2pyrazinones. I t i s worth n o t i n g t h a t these p y r a z i n o n e s were o n l y i d e n t i f i e d i n t h e d i g l y c i n e , t r i g l y c i n e and t e t r a g l y c i n e , but n o t i n the f r e e g l y c i n e system.
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1
1
1
1
1
1
T a b l e I I shows the p y r a z i n o n e s i d e n t i f i e d i n t h e r e a c t i o n o f glucose with e i t h e r g l y - l e u or leu-gly. I t was found t h a t the d i p e p t i d e s , g l y - l e u and l e u - g l y , produced t h e same type o f p y r a z i n o n e s . Q u a n t i t a t i v e l y , both d i p e p t i d e s produced s i m i l a r amounts o f p y r a z i nones. The o n l y p o s s i b l e e x p l a n a t i o n f o r t h i s phenomenon i s t h a t t h e g l y - l e u d i p e p t i d e i s i n e q u i l i b r i u m w i t h the l e u - g l y d i p e p t i d e .
Comparison of the M a i l l a r d Reaction of Glucose with Glutathione and a Mixture of t h e i r Constituent Amino Acids (glu, cys and gly) I t i s known from o u r p r e v i o u s study (20) t h a t t h e r e l e a s e o f hydrogen s u l f i d e was much f a s t e r than ammonia d u r i n g t h e thermal d e g r a d a t i o n o f g l u t a t h i o n e (γ-Glu-Cys-Gly) i n an aqueous s o l u t i o n . However, t h e r e l e a s e o f both hydrogen s u l f i d e and ammonia from c y s t e i n e was f a s t and produced f o u r times as many v o l a t i l e s as g l u t a t h i o n e under t h e same c o n d i t i o n s (20). On t h e o t h e r hand, when c y s t e i n e and g l u t a thione reacted with 2,4-decadienal, r e s p e c t i v e l y , the y i e l d o f v o l a t i l e g e n e r a t i o n became almost i d e n t i c a l . T h i s phenomena was a t t r i b u t e d t o t h e f a c t t h a t c a r b o n y l s , such as 2 , 4 - d e c a d i e n a l and t h e i r r e t r o a l d o l i z a t i o n p r o d u c t s , c a t a l y z e d the ammonia r e l e a s e d from g l u t a t h i o n e v i a the f o r m a t i o n o f t h e S c h i f f - b a s e (21). We compared the M a i l l a r d r e a c t i o n o f e q u i m o l a r s o l u t i o n s o f g l u c o s e w i t h g l u t a t h i o n e (G-G) and i t s c o n s t i t u e n t amino a c i d s (GGCG) i n an aqueous medium. Each r e a c t i o n s o l u t i o n was a d j u s t e d t o pH 7.5 and heated f o r one hour a t 180°C. The r e a c t i o n mass was s i m u l t a n e o u s l y s o l v e n t - e x t r a c t e d and s t e a m - d i s t i l l e d by u s i n g d i e t h y l ether with a Likens-Nickerson apparatus. The d i s t i l l a t e s were d r i e d over anhydrous sodium s u l f a t e and c o n c e n t r a t e d w i t h a KudernaD a n i s h a p p a r a t u s t o a f i n a l volume o f 0.5 mL. The c o n c e n t r a t e d sam p l e s were a n a l y z e d by GC/MS as d e s c r i b e d p r e v i o u s l y (22). A more r o a s t e d and n u t t y aroma was observed i n the G-GCG system than i n t h e
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
Peptides as Flavor Precursors in Model Maillard Reactions 197
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15. HO ET AL
F i g u r e 2. Mechanism f o r the f o r m a t i o n o f 1 , 6 - d i m e t h y l - 2 ( 1 H ) p y r a z i n o n e from p y r u v a l d e h y d e and d i g l y c i n e .
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
198
FLAVOR PRECURSORS
T a b l e I I . The Amount o f P y r a z i n o n e s Generated Reaction o f Glucose with E i t h e r G l y - l e u or Leu-gly
from t h e
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tS 3 R 1-- m e t h y l - 3 - i s o b u t y l 2(1H)-pyrazinone 1- i s o p e n t y l - 2 ( l H ) pyrazinone 1,6-dimethyl-3-isobutyl2(1H)-pyrazinone 1,5,6-trimethyl-3isobutyl-2(lH)pyrazinone
lie
LG
166
GL mg/mole p e p t i d e 351.41 1397
433.59
166
1432
185.58
129.95
180
1562
1629.69
1234.09
194
1638
84.17
83.54
MW
G-G system. The i d e n t i f i c a t i o n and q u a n t i f i c a t i o n o f v o l a t i l e s gene r a t e d i n these two systems a r e l i s t e d i n T a b l e I I I a c c o r d i n g t o t h e i r chemical c l a s s i f i c a t i o n s . I t i s i n t e r e s t i n g t o note t h a t about t h e same q u a n t i t y o f f u rans were produced by the G-G and G-GCG systems, however, t h e amino a c i d s m i x t u r e y i e l d e d 5.6 times the amount o f c a r b o n y l compounds than t h e g l u t a t h i o n e system. Furans a r e t h e c y c l i z a t i o n p r o d u c t s o f the s u g a r - d e r i v e d M a i l l a r d i n t e r m e d i a t e s and the c a r b o n y l compounds are g e n e r a l l y d e r i v e d from t h e f r a g m e n t a t i o n o f sugar. The h i g h e r c o n t e n t s o f the f r e e amino groups i n the G-GCG system may f a v o r the sugar d e g r a d a t i o n r e a c t i o n t o y i e l d c a r b o n y l compounds such as 3hydroxy-2-pentanone and 2-hydroxy-3-pentanone. The g e n e r a t i o n o f h e t e r o c y c l i c compounds such as p y r a z i n e s , t h i a z o l e s and t h i o p h e n e s from t h e G-GCG system had a much h i g h e r y i e l d than from t h e G-G system. The amino a c i d s m i x t u r e produced 14 times more p y r a z i n e s than t h e g l u t a t h i o n e when r e a c t e d w i t h glucose. The t r i t h i o l a n e s and t e t r a t h i a n e s i d e n t i f i e d a r e well-known i n t e r a c t i o n p r o d u c t s o f hydrogen s u l f i d e and a c e t a l d e h y d e , b o t h o f which a r e t h e d e c o m p o s i t i o n p r o d u c t s o f c y s t e i n e . The G-GCG system produced 32 times more o f these c y c l i c p o l y s u l f i d e s . Although g l u t a t h i o n e i s e f f i c i e n t i n r e l e a s i n g hydrogen s u l f i d e , i t may n o t be a good p r e c u r s o r f o r the g e n e r a t i o n o f a c e t a l d e h y d e .
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
15. HO ET A L
Peptides as Flavor Precursors in Model Maillard Reactions 199
T a b l e I I I . V o l a t i l e Compounds I d e n t i f i e d from the I n t e r a c t i o n of G l u c o s e w i t h G l u t a t h i o n e o r G l u t a t h i o n e ' s C o n s t i t u e n t Amino A C i d s ( G l u , Cys, G l y ) i n an Aqueous S o l u t i o n a t pH 7.5 and 180°C MW
I k
86 72 88 74 86 100 88 84 90 100 102 102 104 114 118 96
561 572 599
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Compounds Carbonyls diacetyl 2-butanone ethyl acetate hydroxyacetone 2-pentanone 2. 3-pentanedione acetoin 3-penten-2-one l-mercapto-2-propanone 2,4-pentanedione 3-hydroxy-2-pentanone 2-hydroxy-3-pentanone 3-mercapto-2-butanone 2,4-hexanedione 4-hydroxy-3-hexanone 2-cyclohexenone T o t a l Amount Furans 2-methylfuran 2,5-dihydrofuran 2,5-dimethylfuran 2,3-dihydro-4methylfuran 2-methyltetrahydrofuran-3-one furfural furfuryl alcohol 2-acetylfuran 2,5-dimethyl-3(2H)furanone 5-methylfurfural 5-methyl-2-acetylfuran l-(2-furyl)-l,2propanedione T o t a l Amount Thiophenes thiophene 2,3-dihydrothiophene 2-methylthiophene 3-methylthiophene 2-ethylthiophene 2,5-dimethylthiophene 2 ,3-dimethylthiophene tetrahydrothiophen3-one 5-methyltetrahydrothiophene-3-one
mg/mol. Glutathione Glu+Cys+Gly 1..83 4..34 15.,56
-
-
667 668 680 719 741 758 773 782 787 859 865 904
3..60 0..82 0..31
26..46 82 70 96 84
4.64 72.53 t t t
-
t 1.28 t 41.99 18.28 t 2.22 1.30 5.79 148.03
-
t t 0.54 t
699
-
100
776
9..26
17.08
96 98 110 112
809 835 882 922
9..95 0.88 23,.12
1.19 6.52 5.88 1.15
110 124 138
934 1019 1034
111,.01 2,.13 2,.61
111.46
158,.96
143.82
t
84 86 98 98 112 112 112 102
648 756 760 844 853 877 912
21 .71 1 .69 0 .61 0 .81 19 .43
19.38 t 64.96 17.08 0.35 t t 90.73
116
946
1 .52
5.50
-
Continued on next page In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
FLAVOR PRECURSORS
200
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Table I I I . MW Compounds Thiophenes C o n t i n u e d 2 - m e t h y l t e t r a h y d r o t h i o - 116 phene-3-one 112 thiophene-2-carboxyaldehyde 112 thiophene-3-carboxyaldehyde l-(2-thienyl)130 ethanethiol 2-acetylthiophene 125 126 methylformylthiophene 3-acetylthiophene 126 126 5-me t h y 1 - 2 - f o r m y l thiophene 3-methyl-2-formyl126 thiophene 5-me t h y 1 - 2 - a c e t y l 140 thiophene 3-methy1-2-acetyl140 thiophene 2-(1-propionyl)140 thiophene methylacetylthiophene 140 thenio-[3,2-B]140 thiophene 3 - m e t h y l - 2 - ( o x o p r o p y l ) - 154 thiophene 144 2,5-dimethyl-4hydroxy-3(2H)thiophene 135 thieno-[2,3-C]~ pyridine 154 5-methylthieno[2 ,3-B]-thiophene 168 5-ethylthieno[2,3-D]-thiophene T o t a l Amount Thiazoles thiazole 85 2-methylthiazole 99 4-methylthiazole 99 5-methylisothiazole 99 5-methylthiazole 99 2,5-dimethyl113 thiazole 113 5-ethylthiazole 113 3,5-dimethylisothiazole trimethy1thiazole 127 2-acetylthiazole 127 127 trimethylisothiazole
L*k
Continued mg/mol. Glu+Cys+Gly Glutathione
953
9.74
55.64
958
4.40
38.42
967
9.95
12.05
1035
-
6.13
1049 1054
11.20 2.16
150.09 30.56
1058 1086
24.31 11.49
177.93 27.54
1089
5.20
65.73
1128
8.85
31.37
1135
3.34
3.51
1153
1.31
-
-
34.70 60.67
1192
2.59
-
1195
-
2.98
1213
-
2.75
1282
1.45
20.11
1380
-
6.58
1174 1185
-
141.76
924.76
707 783 795 820 827 860
9.53 1.29 2.57 1.09
95.97 t 2.00 t 3.09 4.44
-
-
t t
977 988
0.45 21.68
-
-
9.35 39.56 t
-
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
15. HO ET A L
Peptides as Flavor Precursors in Model Maillard Reactions 201 Table
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MW
III.
*
mg/molT
I*k
Compounds T h i a z o l e s Continued 4-methy1-2-acetyl141 1083 thiazole T o t a l Amount Pyrazine pyrazine 80 710 methylpyraz ine 94 799 2,5-dimethyl108 888 pyrazine 2-ethylpyrazine 108 893 2,3-dimethypyrazine 108 897 2-methy1-5-ethyl122 977 pyrazine 122 trimethylpyrazine 979 2-methyl-6-ethyl122 984 pyrazine 3,6-dimethyl-2136 1059 ethylpyrazine 5,6-dimethyl-2136 1065 ethylpyrazine T o t a l Amount Pyridines pyridine 79 2-methylpyridine 93 798 T o t a l Amount Other S u l f u r - c o n t a i n i n g Compounds 2-pentanethiol 104 838 4H-tetrahydrothio116 1011 pyran-4-one 152 3,5-dimethyl-l,2,41103 trithiolane 3,5-dimethyl-l,2,4152 1110 trithiolane 184 1345 3,6-dimethyl-l,2,4, 5-tetrathiane 184 1352 3,6-dimethyl-l,2,4, 5-tetrathiane 4,6-dimethyl-l,2,3, 184 1368 5-tetrathiane 4,6-dimethyl-l,2,3, 184 1396 5-tetrathiane T o t a l Amount a
Continued
Glutathione
Glu+Cys+Gly
0.88
6.94
37.49
161.35
-
113.46 73.44 107.41
13.09 8.19 1.06 2.52
3.91
-
15.31 16.65 5.68 47.06 7.82
-
10.01
t
1.68
28.77
398.52
-
t 5.20 5.20
0.44
1.69 2.71
1.49
89.93
4.40
101.23
-
-
10.12
-
5.69
0.70
3.79
-
0.38
7.03
215.54
t = trace Iir = l i n e a r r e t e n t i o n i n d i c e s were o b t a i n e d by u s i n g p a r a f f i n s t a n d a r d s on a n o n p o l ar fused s i l i c a c a p i l l a r y column (60 m χ 0.25 mm [ i . d . ] ) ; 0.25 ym t h i c k n e s s ; DB- l ; J&W S c i e n t i f i c )
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
202
FLAVOR
PRECURSORS
Acknowledgement s New J e r s e y A g r i c u l t u r a l E x p e r i m e n t S t a t i o n P u b l i c a t i o n No. D-1054414-91 s u p p o r t e d by S t a t e f u n d s , and t h e C e n t e r f o r Advanced Food Technology. The C e n t e r f o r Advanced Food T e c h n o l o g y i s a member o f the New J e r s e y Commission f o r S c i e n c e and T e c h n o l o g y . We thank Mrs. Joan B. Shumsky f o r h e r s e c r e t a r i a l a i d .
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Literature Cited 1. 2.
Hodge, J. E. J. Agric. Food Chem. 1953, 1, 928-43. Shigematsu, H.; Shibata, S.; Kurata, T.; Kato, H.; Fujimaki, M. J. Agric. Food Chem. 1975, 23, 233-37. 3. Tressl, R.; Rewicki, D.; Helak, B.; Kamperschroer, H.; Martin, N. J. Agric. Food Chem. 1985, 33, 919-23. 4. Tressl, R.; Rewicki, D.; Helak, B.; Kamperschroer, H. J. Agric. Food Chem. 1985, 33, 924-28. 5. Tressl, R.; Helak, B.; Koppler, H.; Rewicki, D. J. Agric. Food Chem. 1985, 33, 1132-37. 6. Tressl, R.; Grunewald, G.K.; Kersten, E.; Rewicki, D. J. Agric. Food Chem. 1985, 33, 1137-42. 7. Baltes, W.; Bochmann, G. J. Agric. Food Chem. 1987, 35, 340-46. 8. Shu, C-K; Ho, C-T J. Agric. Food Chem. 1988, 36, 801-03. 9. Zhang, Y.; Ho, C-T. J. Agric. Food Chem. 1991, 39, 760-63. 10. Hartman, G. J.; Scheide, J. D.; Ho, C-T Perf. Flav. 1984, 8(6), 81-6. 11. Olsson, K.; Pernelmalm, P. Α.; Theander, O. Acta Chem. Scand. 1978, B32, 249-56. 12. Hayase, F.; Kim, S. B.; Kato, H. Agric. Biol. Chem. 1985, 49, 2337-41. 13. Takahashi, K.; Tadenuma, M.; Kitamoto,K.; Sato, S. Agric. Biol. Chem. 1973, 38, 927-32. 14. Mabrouk, A. F. In Phenolic, Sulfur and Nitrogen Compounds in Food Flavors; Charalambous, G.; Katz, I., Eds.; Acs Symp. Ser. 26; American Chemical Society: Washington, DC, 1976; p. 146-83. 15. Manley, C. H.; McCann, J. S.; Swaine, Jr., R. L. In The Quality of Foods and Beverages; Charalambous, G.; Inglett, G., Eds.; Academic Press: New York, 1981, Vol. 1; p 61-82. 16. Chuyen, Ν. V.; Kurata, T.; Fujimaki, M. Agric. Biol. Chem. 1972, 37, 327-34. 17. Rizzi, G. P. In Thermal Generation of Aromas; Parliment, T. H.; McGorrin, R. J.; Ho, C-T, Eds.; ACS Symp. Ser. 409; American Chemical Society: Washington, DC, 1989; p 285-301. 18. Oh, Y-C; Shu, C-K; Ho, C-T J. Agric. Food Chem. 1991, 39, 1553-54. 19. Hayase, F.; Kato, H.; Fujimaki, M. Agric. Biol.Chem. 1975, 39, 741-42. 20. Zhang, Y.; Chien, M.; Ho, C-T. J. Agric. Biol. Chem. 1988, 36, 992-96. 21. Zhang, Y. Ho, C-T J. Agric. Food Chem. 1989, 37, 1016-20. 22. Zhang, Y.; Ho, C-T J. Agric. Food Chem. 1991, 39, 760-63. RECEIVED December 18, 1991 ;
In Flavor Precursors; Teranishi, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.