Chapter 45
Aroma Development in Chinese Fried Pork Bundle 1
Tzou-Chi Huang, Sen-Far Chang, Chi-Shen Lin, Daniel Y.-C. Shih , and Chi-Tang Ho Downloaded by UNIV OF ROCHESTER on May 3, 2017 | http://pubs.acs.org Publication Date: October 3, 1989 | doi: 10.1021/bk-1989-0409.ch045
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Department of Food Science, National Pingtung Institute of Agriculture, Pingtung, Taiwan, Republic of China
Fried pork bundle is one of the most popular Chinese breakfast foods. Characterized by i t s sensational flavor, color and texture, fried pork bundle is pre pared by (1) b o i l i n g prerigor meat from animals not e l e c t r i c a l l y shocked; (2) predrying the cooked and seasoned meat by conductive heat with scraping on the heating surface and (3) f i n i s h drying the d i s i n t e grated and p a r t i a l l y - d r i e d muscle bundle with added lard and wheat f l o u r . In this study, a headspace GC-MS technique was used to analyze the v o l a t i l e com pounds. Pyrazines were found to contribute to the unique flavor of the f r i e d pork bundle. Free reducing sugars and amino acids from pork muscle may be pre cursors in browning reactions that generate pork bundle aroma. F r i e d and d i s i n t e g r a t e d pork bundle (Zou-Shung) i s c h a r a c t e r i z e d by i t s s p e c i a l shape, f l a v o r , c o l o r and m o u t h f e e l . Low temperature c o o k i n g i n the i n i t i a l s t a g e o f p r o d u c t i o n removes m o i s t u r e , and h i g h temperature i n the f i n a l stage forms i t s c h a r a c t e r i s t i c f l a v o r , u n d e s i r a b l e f l a v o r f r e q u e n t l y o c c u r s i f the p r o d u c t i s heated too long. Optimum h e a t i n g i s judged c u r r e n t l y by the appearance o f a brown c o l o r . F r i e d pork bundle u s u a l l y s u f f e r s poor u n i f o r m i t y i n c o l o r and f l a v o r . T h i s r e p o r t d e s c r i b e s the f l a v o r and c o l o r de velopment d u r i n g the p r o c e s s i n g o f Chinese pork b u n d l e . Manufacturing Process T r a d i t i o n a l l y pork bundle i s homemade. I n t h i s s t u d y , muscle o f Rectus femoris was s l i c e d i n t o 20 χ 10 χ 10 cm cubes and b o i l e d i n water ( 1 0 0 ° C ) f o r 1.5 hours t o denature the muscle p r o t e i n . When 3
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Current address: Department of Food Science, New Jersey Agricultural Experiment Station, Cook College, Rutgers, The State University of New Jersey, P.O. Box 231, New Brunswick, ΝJ 08903 0097-6156/89/0409-0487$06.00/0 ο 1989 American Chemical Society Parliment et al.; Thermal Generation of Aromas ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
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most o f the water was e v a p o r a t e d , s u c r o s e and s a l t were added t o y i e l d seasoned pork b u n d l e . A s t a i n l e s s s t e e l ( d i a m e t e r 1 m) f r y i n g pan, w i t h s e v e r a l s c r a p i n g k n i v e s on the b o t t o m , was used t o f r y the pork b u n d l e s . The s c r a p i n g k n i f e d i s i n t e g r a t e d the muscle cubes i n t o bundles w i t h a d i a m e t e r o f 3-10 mm. The average temperature o f the pork i n the f r y i n g pan was about 8 0 ° C . A p e r i o d o f 70-80 minutes was needed t o remove n e a r l y 75% w a t e r , and the average f i n a l water a c t i v i t y was 0 . 7 0 . The p a r t i a l l y d r i e d and d i s i n t e g r a t e d pork bundle was f u r t h e r f r i e d i n the same f r y i n g pan t o form the d e s i r e d c o l o r , f l a v o r and m o u t h f e e l . I n the f i n a l f r y i n g s t a g e , wheat f l o u r was added t o absorb l a r d and coat the s u r f a c e .
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Sensory E v a l u a t i o n F i n i s h e d f r i e d pork bundles were poured out o f the pan when a brown c o l o r d e v e l o p e d . An eight-member p a n e l was t r a i n e d i n f o u r s e c t i o n s t o become f a m i l i a r w i t h the p r o d u c t s , t o e v a l u a t e the f l a v o r and odor o f pork b u n d l e s . P a n e l i s t s s c o r e d the aroma a t t r i b u t e s by t a s t i n g ( f l a v o r ) o r s n i f f i n g ( o d o r ) , m a r k i n g a 15 cm, 6 0 - p o i n t u n s t r u c t u r e d i n t e n s i t y s c a l e ( e x . 0 = no f l a v o r , and 60 = a s t r o n g flavor). The s c o r e s were c o l l e c t e d and a n a l y z e d by the Response S u r f a c e Method used i n the SAS I n s t i t u t e ( C a r y , N o r t h C a r o l i n a ) t o o b t a i n a r e g r e s s i o n model f o r p l o t t i n g a response s u r f a c e g r a p h . As shown i n F i g u r e 1, a brown c o l o r s t a r t e d t o d e v e l o p a f t e r 90 minutes o f f r y i n g , and f l a v o r formed r i g h t a f t e r the appearance o f the brown c o l o r . Model systems composed o f the seasoned pork b u n d l e , s u c r o s e and l a r d were used t o i n v e s t i g a t e the e f f e c t o f the f r y i n g temperature and l a r d c o n t e n t on f l a v o r and c o l o r development i n C h i n e s e f r i e d pork b u n d l e . Seasoned pork b u n d l e s were p r e p a r e d as d e s c r i b e d p r e v i o u s l y , except superheated steam was used t o p r o v i d e the v a r i o u s h e a t i n g temperatures f o l l o w i n g the d e s i g n s o f Box and Behnken ( 1 ) . As shown i n F i g u r e 2 , the raw meaty odor o f pork bundles dec r e a s e d as the h e a t i n g temperature i n c r e a s e d , w h i l e i n c r e a s e s i n l a r d c o n t e n t had no s i g n i f i c a n t e f f e c t . A possible explanation i s t h a t the raw meaty odor was c o v e r e d by the f l a v o r formed d u r i n g heating. F r y i n g temperature was found t o be the c r i t e r i a l parameter t h a t determined the f l a v o r q u a l i t y i n C h i n e s e pork b u n d l e . Cooked meat aroma i n c r e a s e d as the h e a t i n g temperature v a r i e d from 134°C t o 1 7 2 ° C , as shown i n F i g u r e 3 . Below 130°C n e i t h e r cooked meat aroma n o r brown c o l o r d e v e l o p e d . S l i g h t l y h i g h e r temperatures have been r e p o r t e d f o r the optimum f l a v o r f o r m a t i o n i n f r i e d p o t a t o c h i p s at 180°C ( 2 ) , and r o a s t e d beans at 200°C ( 3 ) . Amino a c i d a n a l y s i s c o n f i r m e d t h a t M a i l l a r d browning r e a c t i o n s o c c u r r e d d u r i n g the f r y i n g p r o c e s s , s i n c e b a s i c amino a c i d s such as l y s i n e and a r g i n i n e d e c r e a s e d s i g n i f i c a n t l y , whereas a l l o t h e r s decreased only s l i g h t l y (Table I ) . Pyrazine Formation A l k y l p y r a z i n e s have been i d e n t i f i e d i n v i r t u a l l y a l l r o a s t e d f o o d s . The most common d e s c r i p t i o n s used f o r a l k y l p y r a z i n e aroma i n c l u d e
Parliment et al.; Thermal Generation of Aromas ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
Downloaded by UNIV OF ROCHESTER on May 3, 2017 | http://pubs.acs.org Publication Date: October 3, 1989 | doi: 10.1021/bk-1989-0409.ch045
45.
HUANG ET AL.
Aroma Development in Chinese Fried Pork Bundle
10
SO
TIME
100
(min)
F i g u r e 1. Development o f redness and aroma d u r i n g the f r y i n g o f pork b u n d l e .
F i g u r e 2. The e f f e c t o f temperature and l a r d c o n t e n t meat aroma o f Chinese f r i e d pork b u n d l e .
on the raw
Parliment et al.; Thermal Generation of Aromas ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
489
THERMAL GENERATION OF AROMAS
Downloaded by UNIV OF ROCHESTER on May 3, 2017 | http://pubs.acs.org Publication Date: October 3, 1989 | doi: 10.1021/bk-1989-0409.ch045
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100
F i g u r e 3 . The e f f e c t o f temperature and l a r d c o n t e n t on cooked meat aroma o f Chinese f r i e d pork bundle •
Table
the
Compositions i n I . Amino A c i d Chinese F r i e d Pork Bundles Pork Bundle
Amino A c i d Asp Thr Ser Glu Pro Gly Ala Cys Val Met He Leu Tyr Phe Lys His Arg
Seasoned 5.3 2.7 3.2 9.5 2.6 2.7 4.1 0.6 3.6 1.3 2.2 3.7 0.4 2.2 6.4 1.3 5.4
Fried 4.8 2.2 2.7 8.9 2.1 2.4 3.3 0.3 3.1 0.8 1.6 3.1 0.2 1.9 3.9 0.8 3.8
Parliment et al.; Thermal Generation of Aromas ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
Downloaded by UNIV OF ROCHESTER on May 3, 2017 | http://pubs.acs.org Publication Date: October 3, 1989 | doi: 10.1021/bk-1989-0409.ch045
45.
HUANG ET AL.
Aroma Development in Chinese Fried Pork Bundle
n u t t y , r o a s t e d and c o r n y . I n the p r e s e n t s t u d y , a s e l e c t i v e purgea n d - t r a p method was developed t o i n v e s t i g a t e p y r a z i n e f o r m a t i o n i n the pork bundle samples. Powdered samples were soaked w i t h water i n a two-arm round bottom f l a s k . V o l a t i l e compounds were purged w i t h n i t r o g e n and trapped w i t h 1 M HC1 s o l u t i o n i n an Erlenmeyer f l a s k . A f t e r t i t r a t i o n t o pH 13, the b a s i c f r a c t i o n was purged w i t h n i t r o gen and trapped on a Tenax TA g l a s s t u b e ; a n a l y s i s was performed on a V a r i a n 3400 gas chromatograph and a F i n n i g a n MAT 8230 h i g h r e s o l u t i o n mass s p e c t r o m e t e r . The b a s i c f r a c t i o n o f the v o l a t i l e s i d e n t i f i e d i n the f r i e d pork bundle c o n t a i n e d 16 a l k y l p r y a z i n e s . Among them, m e t h y l p y r a z i n e (nutty, roasted), 2,5-dimethylpyrazine ( g r i l l e d chicken, roasted peanut), 2,6-dimethylpyrazine ( e t h e r - l i k e ) , 2,3,5-trimethylpyrazine ( n u t t y , r o a s t e d ) and 2 - e t h y l - 6 - m e t h y l p y r a z i n e ( g r a s s y ) were p r e dominant. The c o m b i n a t i o n o f these a l k y l p y r a z i n e s may cause the c h a r a c t e r i s t i c cooked meat aroma o f C h i n e s e f r i e d pork b u n d l e . Q u a n t i t a t i v e a n a l y s e s showed t h a t a l k y l p y r a z i n e formed d u r i n g the f i n a l f r y i n g s t a g e s , as shown i n T a b l e I I . Table I I .
A l k y l p y r a z i n e s i n Seasoned and F r i e d Pork Bundle Pork Bundle (ppm)
Alkylpyrazines pyrazine methylpyrazine 2,5-dimethylpyrazine 2,6-dimethylpyrazine 2 , 3 - d ime t h y l p y r a z i n e vinylpyrazine 5-methyl-2-ethylpyrazine 6-methyl-2-ethylpyrazine 3-methyl-2-ethylpyrazine propylpyrazine 2-methyl-vinylpyrazine 3,6-dimethyl-2-ethylpyrazine 3,5-dimethyl-2-ethylpyrazine tetramethylpyrazine 6-methyl-2,6-diethylpyrazine 3-methyl-2,6-diethylpyrazine
Seasoned 0.2 3.6 12.5 4.2 2.1 0.6 0.2 3.8 6.4 1 trace 9.3 1.1 0.8 0.6 0.1
Fried 0.3 7.3 16.4 6.7 4.1 1.2 0.8 5.3 8.1 2.5 0.5 12.5 2.9 1.6 1.2 0.5
Literature Cited 1. Box, G. E. P.; Behnken, D. W. Technometrics 1960, 2, 455. 2. Maga, J. Α.; Sizer, C. E. Lebensm-Wiss. u. Technol. 1978, 11, 181. 3. Doi, Y.; Tsugita, T.; Kurata, T.; Kato, H. Agric. Biol. Chem. 1980, 44, 547. RECEIVED May 11, 1989
Parliment et al.; Thermal Generation of Aromas ACS Symposium Series; American Chemical Society: Washington, DC, 1989.
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