酱油电渗析液用于酱油制曲的研究

Application of soy sauce electrodialysis brine in the koji-making of soy sauce

将酱油电渗析脱盐过程中分离得到的酱油电渗析液(SSEB)作为浸润黄豆的介质应用于酱油制曲。测定成曲及酱醪的理化指标、挥发性风味物质等,并对成曲及酱醪的微生物构成进行分析。结果表明,控制SSEB制曲过程中黄豆盐分含量为3%(湿质量),在此条件下培养得到的曲料中菌落总数降低且酵母菌数不会受到显著影响,成曲中性蛋白酶活力为(941±18)U。样品在制曲及发酵阶段均显现出了更大的微生物多样性,成曲中优势细菌为葡萄球菌属(Staphylococcus);发酵后期酱醪优势细菌为四联球菌属(Tetragenococcus)与葡萄球菌属(Staphylococcus),真菌菌群以米勒酵母属(Millerozyma)与结合酵母属(Zygosaccharomyces)为主。SSEB制曲的酱油氨基酸氮含量均达到0.8 g/100 mL以上,总酸含量降低了22.50%,挥发性风味物质中高级醇以及酸类物质含量相对较高,感官方面呈现出了令人愉悦的豉香与醇香,有效降低了非有益菌繁殖所带来的异杂味。研究表明,以SSEB进行制曲可促进发酵有益菌建立菌群优势,对酱油风味改善的同时具有维护发酵稳态与酱油生物安全性的潜力。

Koji of soy sauce was prepared by using the soy sauce electrodialysis brine(SSEB)obtained from the desalination process of soy sauce by electrodialysis as a medium for soaking soybeans.The physicochemical indexes and volatile flavor substances of finished koji and soy sauce mash were determined,and the microbial composition was analyzed.The results showed that when the salt content of soybeans in the koji-making with SSEB process was controlled at 3%(wet mass),the total number of bacterial colonies in the koji was reduced,while the number of yeasts was not significantly affected under this condition.The neutral protease activity of the finished koji was(941±18)U.The microbial diversity was higher in samples during both the koji-making and fermentation stages.The dominant bacteria in the finished koji were Staphylococcus,whereas the dominant bacteria were Tetragenococcus and Staphylococcus,the fungal community was dominated by Millerozyma and Zygosaccharomyces in the later stages of fermentation.The amino acid nitrogen content in the soy sauce made with SSEB reached above 0.8 g/100 ml,the total acid content was reduced by 22.50%.And the contents of higher alcohols and acids among the volatile flavor substances were relatively high,which contributed to a delightful fermented soybean aroma and bouquet aroma,effectively reducing off-flavors caused by the proliferation of non-beneficial bacteria.The study demonstrated that employing SSEB for koji-making could promote the establishment of beneficial bacterial communities during fermentation,improve the flavor of soy sauce,and maintain fermentation homeostasis and the biological safety of soy sauce.