Fermentation substrate drives flavor differentiation: Multi-omics analysis of flavor formation mechanisms in sour meat fermented by various grains.

This study investigated the influence of different grain fermentation substrates on the flavor development of sour meat. The results indicated that the fermentation substrate in the coix seed group, characterized by its high starch, protein, and fat content, created favorable conditions for the proliferation of Lactiplantibacillus. This promoted the accumulation of flavor compounds, including alcohols, aldehydes, and medium-chain fatty acids, which imparted distinctive grassy and fatty flavors to the product. Additionally, this substrate enhanced the product's sour profile while significantly increasing the levels of umami amino acids. Conversely, Staphylococcus predominated in the tartary buckwheat(TB) and highland barley (HB) groups. Its metabolic activity was primarily involved in the Ehrlich pathway for amino acid degradation. This process enriched aromatic compounds and branched-chain higher alcohols, resulting in rose-like floral aromas and a complex, mellow flavor profile. Latilactobacillus, Lactiplantibacillus, Fusarium, and Epicoccum were identified as the core microbiota in the CS group. Correlation analyses demonstrated that these genera were the primary contributors to flavor development in sour meat fermented with CS. These findings clarify the differential effects of fermentation substrates on the microbial composition of sour meat, thereby driving distinct metabolic pathways and flavor formation.