Characterization of physicochemical properties, volatile compounds and microbial diversities of inoculated Dajiang on industrial scale

Dajiang has a long history of being an important condiment. Previous research on Dajiang has predominantly centered on laboratory-scale studies or extensive durations of natural fermentation, resulting in limited comprehension of the quality variations and microbial community succession in inoculation industrial-scale production. In this study, physicochemical attributes, volatile compounds and microbial communities of industrialized Dajiang were determined. During the fermentation process, notable increases in the content of free amino acids, total acids, volatile compounds and reddish-brown were observed. Aspergillus, Zygosaccharomyces, and Staphylococcus were identified as the dominant microorganisms. While Aspergillus showed a gradual decline in abundance, Zygosaccharomyces and Staphylococcus exhibited an increasing trend. Redundancy analysis revealed salinity as the primary driving force behind the changes in the microbial community during fermentation. Furthermore, Spearman's correlation analysis demonstrated significant positive associations between Zygosaccharomyces and Staphylococcus with the volatile compounds of Dajiang, suggesting their crucial role in shaping the unique flavor profile of Dajiang. This study provides a solid foundation for understanding the alterations in microbial community composition and physicochemical metabolites during industrial-scale inoculation fermentation of Dajiang.