Synergistic fermentation with functional bacteria for production of salt-reduced soy sauce with enhanced aroma and saltiness

Food fermentation with reduced salt may lead to dysbiosis, changes in both aroma and quality, fermentation failure, and increased risk of food safety issues. In this study, salt-reduced (12% NaCl, w/v) soy sauce fermentation was successfully achieved through synergistic approach with functional Weissella paramesenteroides JL-5 and Bacillus amyloliquefaciens JDF1 bacteria. Both the quality and aroma of salt-reduced soy sauce were recovered with restoration of the soy sauce moromi microbial community through inhibition of spoilage bacteria. And the content of biogenic amines in synergistically fermented soy sauce was decreased to 179.75 mg/L. Interestingly, the saltiness of salt-reduced soy sauce was significantly improved due to enhanced production of 3-methy-1-butanol through synergistic fermentation. Moreover, the total number of bacteria in synergistic fermented soy sauce was significantly lower than in low salt controls during 60 days of storage, without adding preservatives. The results helped to explain the role of functional microorganisms during soy sauce fermentation, and provided a theoretical basis for industrial production of salt-reduced soy sauce.