Effects of sorghum variety on fermentation microecology and flavor characteristics of sesame-flavor Baijiu.

Sorghum, the principal raw material for Baijiu fermentation, plays a key role in shaping fermentation microecology and flavor formation. However, the effects of sorghum varietal differences on sesame-flavor Baijiu fermentation remain insufficiently understood. In this study, three sorghum varieties, Hongyingzi (R), Hei'e (B), and a domestic cultivar (G), were compared over two consecutive fermentation rounds. Fermented grain (Jiupei) samples collected at 0, 15, and 50 days were analyzed for physicochemical properties, enzyme activities, microbial communities, volatile compounds in Jiupei and base liquor, and the taste characteristics of the corresponding base liquor. Despite showing similar overall fermentation trends, the three sorghum varieties differed in acid accumulation, starch utilization, microbial succession, and volatile composition. Fungal communities shifted from early Pichia dominance to multi-genus coexistence, whereas bacterial communities progressively converged toward Lactobacillus dominance. A total of 218 and 258 volatile compounds were identified in Jiupei and 176 and 192 in base liquor from the first and second rounds, respectively. Esters were the dominant differential class, and volatile-marker profiles varied among sorghum varieties and fermentation rounds, with no single variety showing consistent enrichment across all sesame-flavor-related compounds. These results indicate that sorghum variety is an important factor associated with microbial assembly and flavor formation during sesame-flavor Baijiu fermentation, and provide a basis for raw material selection and flavor-oriented process optimization.