无凝固剂乳酸菌发酵豆腐贮藏稳定性研究

Research on Storage Stability of Coagulant-Free Tofu Based on Lactic Acid Bacteria Fermentation

为了探究乳酸菌发酵对新型无凝固剂发酵豆腐贮藏过程的影响规律及其机制,本研究以卤水豆腐为对照,对比分析两种豆腐在不同贮藏温度条件下微生物、色泽、pH等指标变化,通过流式细胞仪分析乳酸对豆腐腐败菌膜电位的影响,探讨乳酸菌发酵豆腐具有较长保质期的机制。结果表明:无凝固剂乳酸菌发酵豆腐在4,10和25℃可分别贮藏14,5和2 d,均比卤水豆腐相应延长2 d左右;10℃贮藏过程中,其乳酸菌及芽孢菌数明显低于对照,pH、颜色变化均慢于对照;无凝固剂乳酸菌发酵豆腐在制作过程中的脑花及成型产品中的芽孢菌数明显低于对照,豆腐的有机酸尤其是乳酸的含量是对照的3倍;乳酸对屎肠球菌膜电位的影响较大,可延缓屎肠球菌的生长繁殖。

In order to investigate the influence and its mechanism of lactic acid bacteria fermentation on the new type of coagulant-free fermented tofu during storage,this study used brine bean curd as a control to compare and analyze the changes of microorganism,color,pH and other indexes of the two kinds of bean curd at different storage temperatures.The influence of lactic acid on the membrane potential of spoilage bacteria of bean curd was analyzed by flow cytometry,and the mechanism of long shelf life of fermented bean curd by lactic acid bacteria was discussed.The results showed that the fermented bean curd by lactic acid bacteria could be stored at 4,10 and 25℃for 14,5 and 2 d,respectively,which were about 2 d longer than that of brine bean curd.During storage at 10℃,the number of lactic acid bacteria and spore were significantly lower than that of the control,and the change of pH and color ware slower than that of the control.The number of spore in the brain and molded products of bean curd without coagulant were significantly lower than that of the control,and the content of organic acids,especially lactic acid in bean curd was 3 times than that of the control.Lactic acid has a great influence on the membrane potential of Enterococcus faecium,and can delay the growth and reproduction of Enterococcus faecium.