The fungal community diversity and structure in different colored Jiang-flavor Daqu (yellow, black and white) were investigated by high-throughput sequencing, and the reason for the physicochemical differences between the three Daqu was analyzed. The results showed that the liquefying power of yellow Daqu (YQ) was higher than that of black Daqu (BQ) and white Daqu (WQ), and the fermenting and esterifying power of YQ (1.56 and 22.63 U, respectively) and BQ (1.51 and 22.48 U, respectively) were higher that those of WQ. The dominant fungi in YQ and BQ were Aspergillus, Cladosporium and Phylctinia, while those in WQ were Aspergillus, Thermoascus, and Byssochlamys. In addition, the fungal community structure and species abundance in YQ were similar to those in BQ. Nonetheless, WQ had a great difference in fungal community structure at the genus level from, and low similarity of species to YQ and BQ. Linear discriminant effect size (LEFse) analysis showed that the fungal community structure of different colored Jiang-flavor Daqu differed in terms of Saccharomyces, Thermoascus, Byssochlamys and several other genera with low abundance. The results of this study lay the foundation for the application of functional fungi in Jiang-flavor Daqu, and provide theoretical support for improving the fermentation performance of Jiang-flavor Daqu.

This study employed high-throughput sequencing and ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS)-based untargeted metabolomics to analyze the heterogeneity of physicochemical properties, microbial communities, and metabolites between the crust (QP) and core (QX) of Moutai-flavored Daqu. The results revealed that the starch content, acidity, reducing sugar content, and esterification capacity but not moisture content of QP were higher than those of QX. The spatial heterogeneity of microbial communities was primarily driven by Kroppenstedtia, Virgibacillus, Staphylococcus, Oceanobacillus, Saccharopolyspora, Thermoascus, Thermomyces, Cladosporium, Fusarium, Pseudopithomyces, and several low-abundance genera. Correlation analysis demonstrated that nine genera, such as Bacteroides, Virgibacillus, and Staphylococcus, were positively correlated with starch content, acidity, reducing sugar content, and esterification capacity, Thermoascus and Rhizomucor showed positive correlation with moisture content. Staphylococcus, Virgibacillus, Oceanobacillus, and other genera were positively correlated with the expression of pyrazine. This study provides a theoretical foundation for the functional zoning and the scientific combined utilization of Daqu.