Abstract:
To compare the physicochemical characteristics and microbial community differences among strong-aroma Daqu from Yibin, Luzhou, Deyang, and Chengdu in Sichuan Province, this study utilized national standard testing and high-throughput sequencing methods to analyze various physicochemical indicators and microbial community structures across these regions. Spearman correlation analysis was performed to explore their interrelationships. The results indicated minimal variations in moisture content, starch content, and acidity levels among the regions, all of which met industry standards. Daqu from Chengdu exhibited the highest saccharifying power (397.50 U/g) and liquefaction power (1.35 U/g), while Yibin Daqu showed slightly better esterification power. Both Yibin and Chengdu Daqu demonstrated superior fermentation power. In terms of microbial communities, prokaryotic diversity was significantly higher than that of eukaryotic organisms. Among prokaryotes, the Bacillota phylum displayed four geographically shared dominant groups, whereas the
Bacillus and
Weissella genera showed regional variations. Chengdu Daqu was unique in hosting the distinctive genus Leuconostoc, with the Luzhou region exhibiting the highest prokaryotic richness (Ace index 139.67) and the Deyang region maintaining the highest diversity (Shannon index 2.79). Eukaryotic communities revealed distinct patterns: Ascomycota dominated with over 85% relative abundance,
Aspergillus asperi was universally dominant across regions, and the Deyang region's eukaryotic community exhibited the richest complexity (Ace index 51.17, Shannon index 1.69), contrasting with Chengdu's lowest diversity. Correlation analysis revealed strong positive correlations between
Leuconostoc and
Weissella with saccharification capacity, and
Bacillus with fermentation power. Among eukaryotes,
Saccharomycopsis strongly correlated with saccharification capacity, while
Candida and
Thermoascus showed positive associations with esterification capacity. This study confirms significant regional differences in the physicochemical characteristics and microbial community structures of concentrated Daqu from various production areas in Sichuan, with clear geographical correlations between these factors. It provides theoretical support for the screening of high-quality Daqu and the optimization of brewing technology, and aids the strong aroma liquor industry in developing towards precision and standardization.