Comparative Analysis of Sensory Quality and Microbial Communities Between Medium-High- and High-Temperature Daqu From Shangqiu Region.

Daqu is the backbone of liquor production, and its characteristics significantly influence Baijiu quality. This study explored the differences between MHTD and HTD from China’s Shangqiu region using E-nose analysis, E-tongue analysis, PacBio SMRT sequencing, and pure culture techniques. E-nose and E-tongue analysis showed that HTD exhibited higher sourness, bitterness, and astringency and contained greater amounts of sulfides, alcohols, aldehydes, and ketones (P < 0.05). Meanwhile, MHTD had stronger umami and saltiness and a greater content of aromatic compounds (P < 0.05). Sequencing revealed significant differences in microbial richness and diversity between MHTD and HTD (P < 0.05). Specifically, HTD was dominated by Staphylococcus saprophyticus (40.24%) and Thermomyces lanuginosus (57.27%), whereas MHTD primarily contained Weissella cibaria (16.27%) and Saccharomycopsis fibuligera (32.20%). On correlation analysis, most lactic acid bacteria (LAB) and yeast species showed a positive correlation with WC sensor responses (P < 0.05). Through pure culture, 170 microbial strains were isolated and identified from 20 Daqu samples. Notably, most LAB and yeast isolates were only detected in MHTD. This study provides data support and strain resources for improving the quality of HTD and MHTD and preserving the culturable strains found in these types of Daqu.