The aroma profile and microbiota structure in oil furu, a Chinese fermented soybean curd

The aroma compounds and the microbial community of oil furu, a specific fermented soybean curd, during fermentation were investigated using HS-SPME-GC/MS and high-throughput sequencing, respectively, and their correlations and the predicted functional roles of the microbiota in oil furu were analyzed. Twenty two volatile flavor compounds (relative odor activity value ≥1) were identified that contributed to the aroma profile, which were mainly associated with the aroma attributes. Lactobacillales, Trichosporon and Mucor racemosus were the predominant genera during pre-fermentation, while Candida and Tetragenococcus were predominant during ripening. Correlation analysis showed significant correlation between the microbiota and aroma profiles, and Candida, Empedobacter, Lactobacillus, Pseudomonas, Stenotrophomonas, Trichosporon and Mucor racemosus were significantly and strongly correlated with the characteristic volatile aroma compounds of oil furu (P < 0.05, r > 0.6). Functional analysis showed that metabolic pathways showed higher activity in oil furu, which mainly included amino acid, lipid and carbohydrate metabolism. The results allowed identification of the important aroma compounds and understanding the contribution of the microbiota, and would be useful for designing starter cultures to produce oil furu with desirable aroma properties and understanding its aroma formation pathways.