Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China.
Food Res Int. 2021 Dec;150(Pt A):110741. doi: 10.1016/j.foodres.2021.110741. Epub 2021 Oct 12.
Sauce-flavor baijiu is a representative of Chinese traditional fermented baijiu using grains as the raw materials through the co-fermentation of microorganisms. The whole manufacturing process includes 7 times of distillation and generates 7 kinds of base baijius. The final product is a mixture of the 7 kinds of base baijius. Thus the base baijius greatly affect the quality of the final product. The quality of the base baijiu obtained by the sixth distillation is obviously poorer than that of the fifth one. However, the reason is still unclear and limits the quality control of baijiu fermentation. In this study, the flavor substances and microbiota in the up, middle and bottom layers of fermented grains in the fifth and sixth rounds were compared. Some flavor esters showed obviously decreased concentrations in the sixth round, including ethyl benzoneacetic acid, ethyl hexanoic acid, ethyl dodecanoic acid, diethyl butanedioic acid, and ethyl 2-hydroxyl-propanoic acid. Meanwhile, an off-flavor p-cresol was detected in the sixth round. Correlation analysis of flavor chemicals and microbiota indicated that fungi in the fifth round played an important role for ester synthesis. Some bacterial and fungal species were both positively correlated with p-cresol synthesis, and the related p-cresol metabolic pathways were proposed for the first time. These results revealed flavor divergences of fermented grains between the fifth and sixth rounds, and will ultimately help to improve baijiu quality.
豉香风味白酒是中国传统发酵白酒的代表之一，以谷物为原料，通过微生物的共同发酵而成。整个酿造过程包括 7 次蒸馏，产生 7 种基酒。最终产品是 7 种基酒的混合物。因此，基酒对最终产品的质量有很大的影响。第六次蒸馏得到的基酒质量明显比第五次蒸馏的差。然而，原因尚不清楚，限制了白酒发酵的质量控制。本研究比较了第五轮和第六轮发酵过程中粮糟上、中、下层的风味物质和微生物区系。一些风味酯类在第六轮中表现出明显降低的浓度，包括苯乙酸乙酯、己酸乙酯、十二酸乙酯、丁二酸二乙酯和 2-羟基丙酸乙酯。同时，在第六轮中检测到一种异味物质对甲酚。风味化学物质与微生物区系的相关分析表明，第五轮的真菌对酯类合成起着重要作用。一些细菌和真菌物种与对甲酚的合成呈正相关，首次提出了相关的对甲酚代谢途径。这些结果揭示了第五轮和第六轮发酵过程中糟醅的风味差异，最终有助于提高白酒的质量。
