Analysis of physicochemical properties and microbial succession during storage process of high-temperature Daqu for sauce-flavor Baijiu

Using high-temperature Daqu of sauce-flavor (Jiangxiangxing) Baijiu with different period of storage as research object, the changes of physicochemical indicators and succession patterns of microorganisms during storage process of high-temperature Daqu were evaluated. Canonical correspondence analysis (CCA) was further employed to analyze the correlation between microorganisms and physicochemical properties. The results indicated that the starch contents remained stable, while moisture and acidity showed a decreasing trend, and the liquefaction power, saccharification power and fermentation power exhibited an initial increase followed by a decrease trend during storage process of high-temperature Daqu. High-temperature Daqu of sauce-flavor Baijiu aged for 90-150 d was appropriate. Microbial community structure analysis during storage process revealed that the dominant bacterial genera were Virgibacillus and Kroppenstedtia, the dominant fungal genus was Thermoascus. CCA results indicated that Staphylococcus, Fusarium, Kroppenstedtia, Wallemia, Pseudonocardia, Saccharopolyspora, and Thermoascus were potential microorganisms influencing physicochemical properties of high-temperature Daqu of sauce-flavor Baijiu. Weighted network analysis results shown that Pseudonocardia had relatively strong correlations with multiple physicochemical properties and might be the key microorganism affecting physicochemical properties.