酱油发酵过程中细菌的分离鉴定及其特性与交互作用

本研究从高盐稀态酱油酱渣中筛选细菌菌株,对5株代表性菌株进行理化性质分析探明菌株生长特性,并在模型体系中研究其与酵母的交互作用对菌株繁殖及风味形成的影响。研究后发现,解淀粉芽孢杆菌与枯草芽孢杆菌具有更强的蛋白酶活力,而腐生葡萄球菌、克氏库克菌与约式不动杆菌有更强的生长活力与产酸能力。其中解淀粉芽孢杆菌的耐盐性最差,其生长量相较于无盐状态下降低98.5%。在细菌与酵母交互作用模型中,发现解淀粉芽孢杆菌、枯草芽孢杆菌和腐生葡萄球菌与鲁氏酵母之间存在相互促进生长的作用。如解淀粉芽孢杆菌与酵母的数量分别提升约9.6倍,而腐生葡萄球菌与酵母分别提升约5.2倍。同时,克氏库克菌的单菌与混菌培养体系均具有较好风味特性,提升了乙酸、乙酸乙酯、苯乙醛、3-甲硫基丙醛和3-甲硫基-1-丙醇等香气物质,具有应用潜力。该研究将对酱油发酵中的风味调控提供理论依据。

Identification of Bacteria during Soy Sauce Fermentation and the Study on Their Characteristics and Interactions

In this work, the physicochemical properties of 5 representative bacterial strains, which screened from the residue of high-salt liquid fermentation soy sauce, were analyzed to explore the growth characteristics, and to evaluate the effects of their interaction with yeast on the reproduction and flavor formation in the model system. The results showed that Bacillus amyloliquefaciens and Bacillus subtilis had stronger protease activity, while Staphylococcus saprophyticus, Kocuria kristinae and Acinetobacter johnsonii were stronger in growth activity and acid production. Among them, the salt tolerance of Bacillus amyloliquefaciens was the worst, and its colony-forming units (CFU) decreased by 98.5% compared to that without salt. In the model of interaction between bacteria and yeast, it was found that Bacillus amyloliquefaciens, Bacillus subtilis, Staphylococcus saprophyticus and Zygosaccharomyces rouxii promoted each other''s growth. For example, the number of CFU of Bacillus amyloliquefaciens and yeast could increase by about 9.6 times respectively, while numbers of CFU of Staphylococcus saprophyticus and yeast could increase by about 5.2 times respectively. Meanwhile, Kocuria kristinae and its mixed culture systems had good flavor characteristics, which could improve various aroma compounds, such as acetic acid, ethyl acetate, benzene acetaldehyde, methional, 3-methylthio-1-propanol and so on, and had potential applications. This study will provide theoretical basis for the regulation of flavor in soy sauce fermentation.