Microbial community variation and flavor metabolism in low-salt Chinese horse bean-chili-paste: Insights from bioturbation fermentation

Chinese horse bean-chili-paste (CHCP) is a traditional and famous high-salt fermented condiment in southwest China, and salt reduction strategy in this industry is imperative. In this study, we investigated the effect of inoculation with two endogenous strains (Tetragenococcus halophilus and Wickerhamiella versatilis) on the products quality at different salinity. The results showed that salt reduction combined with microbial inoculation showed prominent impact on the volatile profile. A total of 15 compounds was identified as key flavors, and bioturbation fermentation could significantly promote the concentrations of many pleasant aroma volatiles. Quantitative microbial profile analysis identified 29 key genera that might benefit microbial stability. In addition, bioturbation fermentation stimulated more microbial communities to contribute to the formation of key flavors. Moreover, the metabolic pathways of key flavor compounds were further investigated and preliminary results suggest that bioturbation under low-salt conditions promotes high expression of enzymes involved in the formation of these compounds, thereby increasing the abundance of key flavor compounds. These results revealed the variations of microbial communities in low-salt CHCP after biofortification fermentation and their influences on flavor metabolism, which could provide references for the manufacture of low-salt fermented foods.