Correlation between microbial communities and volatile flavor compounds in the fermentation of Semen Sojae Praeparatum

Abstract

SSP (Sojae Semen Praeparatum, SSP), a traditional medicinal and edible product, undergoes natural fermentation resulting in a unique flavor. However, the complexity of the natural fermentation system results in inconsistent quality. This study utilized E-nose, headspace solid-phase microextraction combined with full two-dimensional gas chromatography-mass spectrometry, and high-throughput sequencing techniques to reveal the correlation between key volatile flavor compounds and dominant microbial communities during SSP fermentation. The results showed that total organic acids increased from 50.61 mg/g to 72.29 mg/g during SSP fermentation, and levels of umami and sweet amino acids significantly increased. Alcohols, esters, and acids were the main flavor compounds during SSP fermentation, with 52 being identified as key volatile flavor compounds. In the microbial community, bacterial communities dominated by Proteobacteria, Cyanobacteria, and Firmicutes exhibited dynamic solid changes, while fungal communities dominated by Ascomycota, Basidiomycota, unclassified_Fungi, and Mortierellomycota showed relatively stable abundance. Spearman correlation analysis showed that 9 dominant microbial genera were significantly correlated with 27 key volatile flavor compounds, among which Cladosporium, Leuconostoc, Weissella, and Lactiplantibacillus may be the core functional microbial community for SSP characteristic flavors. This study provided theoretical references for the targeted control of SSP quality and the screening of starter fermentation cultures.