Unveiling the distinctive features of Feng-flavor Daqu: A comparative study of microbial communities and volatile compounds.

Daqu acts as a multifunctional starter, providing essential microorganisms and enzymes for simultaneous saccharification and fermentation in Chinese Baijiu production. This work aims to reveal the distinct features among Feng-flavor Daqu (FXDQ) and the 3 main flavor types of Baijiu Daqu (Light-, Luzhou-, Sauce-flavor Daqu). FXDQ exhibited lower moisture content, and the higher acidity, esterifying power, liquefaction capacity. Microbially, Bacillus and Actinomyces dominated the bacterial community, whereas Saccharomycopsis was the predominant fungal genus. Across the four Daqu, 130 volatile compounds were detected and 16 of these were identified as key discriminators. Strong correlations were identified among the microbiota, physicochemical properties, enzyme activities, and volatile compounds. Moreover, PICRUSt2 was utilized to predict enzymes associated with the production of some important aroma compounds. These findings enhance our understanding of Daqu, particularly providing deeper insights into the unique characteristics of Feng-flavor Daqu, and offer a scientific basis for optimizing Daqu production processes.