Microbial communities as key drivers: Exploring sorghum quality impact on light-flavor Baijiu through physicochemical and flavor analyses of fermented grains.

Abstract

Light-flavor Baijiu is a Chinese liquor characterized by a short brewing cycle and a relatively simple process, making it an ideal model for evaluating the effects of raw materials on brewing outcomes. This study investigated two glutinous (GS-L, GS-S) and two non-glutinous (NGS-G, NGS-A) sorghum varieties using solid-state fermentation over a period of 0, 15, 30, and 45 days to analyze the evolution of microbial communities, physicochemical properties, and dynamic changes in flavor components. Results showed that sorghum type significantly influenced the microbial communities and function. Klebsiella was exclusively detected in fermentations with glutinous sorghum. Meanwhile Saccharomycopsis dominated these samples throughout the process. Differences in microbial communities between glutinous and non-glutinous sorghum were primarily reflected in fungal genera. Kazachstania, Epicoccum, Fusarium, Hyphopichia, Trichosporon and Alternaria were commonly detected in GS-L and GS-S. Microbial community succession was primarily driven by acidity, amino acid nitrogen, starch, and reducing sugars, with starch and reducing sugars being particularly influential. During fermentation, 129 flavor compounds were discovered. GS-L and GS-S outperformed NGS-G and NGS-A in producing most flavor compounds, exhibiting significantly higher concentrations and greater stability after long-term fermentation. PICRUST II functional prediction revealed significant differences in the relative abundance of genes linked to carbohydrate metabolism, starch and sucrose metabolism and amino acid biosynthesis among sorghum varieties. FUNGuild prediction further indicated that environmental microorganisms also influence fermentation outcomes. These findings provide a basis for selecting raw materials and optimizing fermentation parameters, ultimately contributing to improving Baijiu quality.