Temperature‐dependent alcohol acyltransferase reactions as the main enzymatic way to produce short‐chain (C4–C8) and medium‐chain (C9–C13) esters over the whole Daqu‐making process

• Published in: Journal of the science of food and agriculture 2023-06, Vol.103 (8), p.3939-3949
• Main Authors: Wang, Yan, Du, Yake, Jin, Xuelian, Xia, Yu, Zhao, Yajiao, Wu, Zhengyun, Gomi, Katsuya, Zhang, Wenxue
• Format: Article
• Language: English
• Subjects: Acyltransferase; Acyltransferases - metabolism; alcohol acyltransferase; Alcohols; Chains; Chemical synthesis; Daqu‐making; Environmental factors; Environmental testing; Enzymes; Esters; Esters - chemistry; Fermentation; Flavors; medium‐chain esters; primary metabolism; short‐chain esters; Substrates; Temperature; Temperature dependence
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.12327

BACKGROUND The ester‐synthesis enzymes influenced by environmental factors during Daqu‐making process largely determine the flavor of Chinese liquor, but the main ester‐synthesis enzyme and its key influencer remain unclear. Here, the volatile ester profiles over the whole Daqu‐making process, under different treatments, for at least 90 days, were carefully analyzed, and the potential ester‐synthesis enzymes, as well as their dependently environmental factors, were explored. RESULTS In the detected 46 volatile esters, only the short‐chain (C4–C8) and medium‐chain (C9–C13) ester content obviously changed, as the primary contributor discriminating different samples. Their trends were both consistent with that of the alcohols and the primary metabolism, which included alcohol acyltransferases (AATs) reaction with alcohols and acyl‐CoAs as the substrates. Among the potential ester‐synthesis enzymes, the typical AAT activity also exhibited the highest correlation with the short‐ and medium‐chain esters (r > 0.78, P