Effect of halophilic LAB and yeasts on the quality of high-salt dilute-state soy sauce

Effects of halophilic LAB (Tetragenococcus halophilus) and yeasts (Zygosaccharomyces rouxii and Candida versatilis) on physicochemical properties and volatile compounds of soy sauce mash were investigated. The result showed that the FN of soy sauce mash added with salt-tolerance microorganisms at 125d were higher than that of the control sample (without microorganism addition) , and the TA of soy sauce mash added with T. halophilus was higher than others. No obvious difference was observed in control sample and soy sauce mash added with T. halophilus, Z. rouxii and C. versatilis. Meanwhile, analysis of the changes of RS showed that the halotolerant microorganisms added samples exhibited lower content of RS compared to the control. Moreover, effects of volatile compounds in all soy sauce mash were analyzed by GC-MS. After fermentation for 125d, the contents of alcohols and esters increased, and the contents of acids and miscellaneous compounds reduced. Among the volatile compounds detected, 2-methyl butyric acid, 2-methyl butyl alcohol and isoamyl acetate in T. halophilus added sample were 53.4%, 337.3%, and 388.2% higher than that of the control sample, respectively. The halotolerant yeasts (Z. rouxii and C. versatilis) added samples exhibited 64.2% and 56.3% increase in contents of ethanol and ethyl acetate, respectively than the control sample did. In addition, the contents of 1-octen-3-al and benzaldehyde in the soy sauce mash added with T. halophilus, Z. rouxii and C. versatilis were 56.7% and 26.3% higher than that of control sample, respectively.