Document Detail

Effect of urea on volatile generation from Maillard reaction of cysteine and ribose.
MedLine Citation:
PMID:  10956141     Owner:  NLM     Status:  MEDLINE    
Urea occurs naturally in many food products, and its presence affects food quality. However, little is known about its impact on flavor generation in food production. In this study, the urea contents in beef, pork, and chicken were determined. The effects of urea and pH on thermal flavor generation were investigated using the model system of cysteine with ribose, which was heated to the roasting temperature of 180 degrees C for 2 h at pH 5 and pH 8.5. The results revealed relatively large amounts of urea in these meats and demonstrated that pH affects aroma generation. Volatiles identified from the reaction system of ribose and cysteine showed that sulfur-containing compounds such as thiophenes, thiazoles, and thiophenethiols were the most abundant compounds. The addition of urea into the reaction mixture caused the disappearance or reduction in content of some sulfur-containing compounds but resulted in the generation of several important nitrogen-containing volatiles, like pyrazine, methylpyrazine, 2,5- (and 2,6-)dimethylpyrazine and other alkylpyrazines, which are known to elicit roasty, nutty flavor notes. A plausible explanation for this phenomenon is that ammonia can be released from urea upon heating and the formed ammonia competes with hydrogen sulfide to react with Maillard reaction precursors to produce nitrogen-containing compounds such as alkylpyrazines.
Y Chen; J Xing; C K Chin; C T Ho
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  48     ISSN:  0021-8561     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2000 Aug 
Date Detail:
Created Date:  2000-09-25     Completed Date:  2000-09-25     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3512-6     Citation Subset:  IM    
Department of Food Science and Department of Plant Sciences, Cook College, Rutgers University, New Brunswick, New Jersey 08901-8520, USA.
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MeSH Terms
Cysteine / chemistry*
Maillard Reaction*
Ribose / chemistry*
Urea / chemistry*
Reg. No./Substance:
50-69-1/Ribose; 52-90-4/Cysteine; 57-13-6/Urea

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