Abstract: 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.

Key words: high-temperature Daqu; microbial community; metabolite; correlation analysis