酱油发酵过程中融合魏斯氏乳酸菌促进瓜氨酸的积累

氨基甲酸乙酯是一种广泛存在于发酵食品中的2A级致癌物,除了酒类,发酵豆制品中也有检出。本文以EC含量较高的高盐稀态发酵酱油为主要研究对象,分析了发酵过程中EC形成与尿素和瓜氨酸之间的关系,并探讨了酱油乳酸发酵时期融合魏斯氏乳酸菌(Weissella confusa)积累EC前体瓜氨酸的情况。结果显示酱油发酵液p H为4.8时EC开始形成,且与瓜氨酸含量显著相关,分离该阶段酱醪的乳酸菌发现Weissella confusa为主要菌株,其积累瓜氨酸能力差异很大。瓜氨酸在不含Na Cl培养基中主要在稳定期后释放,而在含18%Na Cl培养基中在生长过程中不断积累。盐胁迫是Weissella confusa积累瓜氨酸的主要原因,适宜的p H和高浓度的葡萄糖也能促进Weissella confusa积累瓜氨酸。

Citrulline Accumulated by Weissella confusa during Soy Sauce Fermented Process

Ethyl carbamate (EC), a widespread by-product in fermented food, was classified as a group 2A carcinogenic compound, in addition to the occurrence of alcoholic beverages, EC can be found in fermented soybean products. In this work, the correlations of EC with urea and citrulline in soy sauce during fermentation were analyzed. Furthermore, the effects of Weissella confusa on the citrulline accumulation were discussed. Results showed that EC in soy sauce fermented liquor was formed when the pH was about 4.8, there was a significant correlation of citrulline with EC content. Lactic acid bacteria were isolated from moromi mash during this stage, and weissella confusa was the main lactobacillus, but their citrulline accumulation abilities were different. Citrulline accumulated stages of Weissella confusa in the medium with or without 18% NaCl are after stationary phase and the whole growing time respectively. The ability to accumulated citrulline by Weissella confusa was activated by saline stress, the optimal pH and high concentrate of glucose accelerated the citrulline accumulation.