Impact of Inoculating with Indigenous Bacillus marcorestinctum YC-1 on Quality and Microbial Communities of Yibin Yacai (Fermented Mustard) during the Fermentation Process

Bacillus species play an important role in improving the quality of some fermented foods and are also one of the dominant bacteria in Yibin Yacai (fermented mustard). However, little is known about their effects on the quality of Yibin Yacai. Here, the effect of Bacillus marcorestinctum YC-1 on the quality and microbial communities of Yibin Yacai during the fermentation process was investigated. Results indicated that the inoculation of Bacillus marcorestinctum YC-1 promoted the growth of Weissella spp. and Lactobacillus spp. and inhibited the growth of pathogens, accelerating the synthesis of free amino acids and organic acids and the degradation of nitrite. Furthermore, inoculating Yibin Yacai with YC-1 could effectively enhance the synthesis of alcohols and terpenoids in yeasts, thus producing more linalool, terpinen-4-ol, and oc-muurolen in Yibin Yacai, and endowing it with pleasant floral, fruity, woody, and spicy aromas. These findings reveal that the inoculation of B. marcorestinctum YC-1 can improve the quality and safety of Yibin Yacai by changing microbial communities as fermentation proceeds.