Characterization of Microbial Community Succession and Flavor Formation During Fermentation in Chinese Northern Strong-Flavor Daqu

Abstract

The aroma of strong-flavor Daqu is a key quality indicator, but its aroma components remain incompletely understood. These compounds stem from microbial metabolism, yet research on northern strong-flavor Daqu microbiota remains scarce. This study utilized physicochemical analyses, gas chromatography-olfactometry-mass spectrometry (GC-O-MS) detection, and Illumina high-throughput sequencing to comprehensively investigate the fermentation process of northern strong-flavor Daqu. Results indicated that both the diversity and contents of volatile compounds increased during fermentation, generating nutty, woody, and roasted aroma notes. A total of 105 volatile substances were identified, of which 21 were identified as the key aroma-active compounds, including ethyl hexanoate, hexanal, and 2,3,5-trimethylpyrazine. Dominant microbial genera identified during Daqu fermentation include Weissella, Lactobacillus, Leuconostoc, Thermoascus, Aspergillus, and Wickerhamomyces. Furthermore, Kroppenstedtia, Saccharopolyspora, Thermoactinomyces, Thermoascus, Aspergillus, Rhizomucor, and Thermomyces emerged as key microorganisms influencing the aroma profile of Daqu. These findings provide a theoretical foundation for quality optimization and standardized production of strong-flavor Daqu.