The quality of beef-soybean paste and the relationship between microbial composition and flavor changes during fermentation

Compound fermented seasonings were increasingly favored by consumers. This study using Aspergillus oryzae and soybeans as raw materials to make koji. Lactobacillus plantarum and Pediococcus pentosaceus were used as starters for common fermentation with mature koji and beef to obtain a fermented beef-soybean paste. The physicochemical parameters, volatile flavor compounds, and microbial community of beef-soybean paste during fermentation were determined, and the relationship between flavor changes and microbial community changes was analyzed. Compared to the soybean paste, the addition of beef for fermentation can significantly enhanced the content of protein, amino acid nitrogen, and free amino acids in the compound fermented soybean paste, improved the nutritional and health value of the product. The addition of beef also caused a decrease in pH and total acid content in the compound soybean paste. The flavor changed during the fermentation process of beef-soybean paste were related to the changed in its microbial community.