Zhang Huaizhi, Zhang Lijie, Yu Xiaowei, Xu Yan
State Key Laboratory of Food Science & Technology, Key Laboratory of Industrial Biotechnology of Ministry of Education & School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
J Agric Food Chem. 2020 Mar 18;68(11):3558-3567. doi: 10.1021/acs.jafc.9b07809. Epub 2020 Mar 3.
2-Ethyl-3,5(3,6)-dimethylpyrazines (EDMPs) have a pleasant aroma of roasted cocoa or nuts with an extreme low odor threshold that have potential in industrial applications as food fragrances. The food fermentation process can accumulate EDMPs, and this might be the chance to study the biosynthesis mechanism of EDMPs under mild conditions for "natural" EDMPs' production. In this study, an EDMP-producing strain was isolated from baijiu fermentation. This strain was identified as , a generally regarded as safe organism. After reasonable assumption and substrate addition and isotope-labeled experiments, we found that EDMPs are produced from l-threonine and d-glucose at environmental temperature and pressure. In addition, aminoacetone, the metabolite of l-threonine, and 2,3-pentanedione, the metabolite of l-threonine and d-glucose, are intermediates for the production of EDMPs. This study proposed and confirmed the biosynthesis pathway of EDMPs. It will be helpful for the industrial production of EDMPs and provides reference for the biosynthetic mechanism analysis of other valuable pyrazines.
2-乙基-3,5（3,6）-二甲基吡嗪（EDMPs）具有令人愉悦的烤可可或坚果香气，气味阈值极低，在作为食用香料的工业应用中具有潜力。食品发酵过程会积累EDMPs，这可能是在温和条件下研究EDMPs生物合成机制以生产“天然”EDMPs的契机。在本研究中，从白酒发酵中分离出一株产EDMPs的菌株。该菌株被鉴定为 ，一种通常被认为是安全的生物体。经过合理假设、底物添加和同位素标记实验，我们发现EDMPs在环境温度和压力下由L-苏氨酸和D-葡萄糖产生。此外，L-苏氨酸的代谢产物氨基丙酮以及L-苏氨酸和D-葡萄糖的代谢产物2,3-戊二酮是EDMPs产生的中间体。本研究提出并证实了EDMPs的生物合成途径。这将有助于EDMPs的工业化生产，并为其他有价值吡嗪的生物合成机制分析提供参考。
