Alkyl pyrazine synthesis via an open heated bath with variable sugars, ammonia, and various amino acids

• Published in: Journal of the science of food and agriculture Vol. 97; no. 7; pp. 2263 - 2270
• Main Authors: Ara, Katayoun Mahdavi, Taylor, Larry T, Ashraf‐Khorassani, Mehdi, Coleman, William M
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-05-2017; John Wiley and Sons, Limited
• Subjects: alkyl pyrazines; Amino acids; Amino Acids - chemistry; Ammonia; Ammonia - chemistry; Chemical synthesis; Foods; Gas Chromatography-Mass Spectrometry; GC‐MS; Headspace volatiles; Hot Temperature; Leucine; Maillard Reaction; open heated bath; Optimization; Pyrazines; Pyrazines - chemical synthesis; Pyrazines - chemistry; rhamnose; Rhamnose - chemistry; Synthesis; GC-MS; rhamnose; alkyl pyrazines; open heated bath; amino acids
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.8039

BACKGROUND
Semi‐quantitative characteristics of headspace volatile pyrazines which constituted around 1% by weight of the final product have been previously described. The influence of reactant concentration, reaction temperature, and reaction time on both the yield of total alkyl pyrazines and the distribution pattern of specific identified pyrazines has not been reported.
RESULTS
The optimum synthetic conditions were 5 mol L−1 NH4OH, 2 mol L−1 rhamnose, 0.5 mol L−1 leucine at 110°C for 2 h. The greatest total amount of pyrazines obtained was 17 280 µg of extracted product which translated into 31% 2,6‐dimethyl pyrazine, 17% 2‐methyl pyrazine, 15% 2‐ethyl‐6‐methyl pyrazine, and 16% 2‐isoamyl‐6‐methyl pyrazine.
CONCLUSION
The yield of synthesized pyrazines increased at higher temperatures. Quantitative total and specific pyrazine results as opposed to analysis of only headspace volatiles are more representative of pyrazine synthesis. © 2016 Society of Chemical Industry