一种百岁老人源罗伊氏乳杆菌益生特性及其发酵水牛乳制备工艺优化

为探索新筛选的一株百岁老人源罗伊氏乳杆菌LT018开发利用价值,本研究首先检测了该菌株在连续培养300代过程中的活菌数、菌活力,判断其遗传稳定性,又对该菌株在模拟胃肠液中存活率及凝集率进行测定,判断该菌株的益生特性。进一步以此菌株与传统保加利亚乳杆菌和嗜热链球菌发酵剂相结合制备发酵水牛乳,在单因素实验的基础上,通过响应面实验探索其最佳工艺。结果显示,在连续培养300代的过程中,罗伊氏乳杆菌LT018的活菌数和菌活力均保持在一个较高的水平;菌株在模拟胃液和肠液中的存活率分别高于99.07%和77.83%;同时保持大于55.4%的凝集率。发酵水牛乳最佳制备工艺为:罗伊氏乳杆菌发酵剂:传统发酵剂为2:1、白砂糖添加量为3.00%、发酵温度为40.00℃,此时发酵乳的感官评分最高(86.63±1.47),罗伊氏乳杆菌活菌数也达到了1.033×108 CFU/mL。本研究为该菌株的开发利用提供了重要的理论和技术参考。

Probiotic Characteristics of Lactobacillus reuteri Derived from Centenarians and the Optimization of Its Fermentation Process for Fermented Buffalo Milk

In order to explore the development and utilization value of a newly screened L. reuteri LT018 strain from centenarians,this study first tested the viable cell count and bacterial vigor of the strain in the process of continuous culture for 300 generations,and judged its genetic stability. The survival rate and agglutination rate of the strain in the simulated gastrointestinal fluid were measured to determine the probiotic characteristics of the strain.Further,this strain was combined with traditional Lactobacillus bulgaricus and Streptococcus thermophilus fermenting agent to prepare fermented buffalo milk.Based on the single factor experiment,the optimal process was explored by response surface experiment.The results showed that the viable count and bacterial viability of L. reuteri LT018 were maintained at a high level during the continuous culture for 300 generations;The survival rate of the strain in the simulated gastric juice and intestinal juice was higher than 99.07% and 77.83%,respectively,while maintaining the agglutination rate greater than 55.4%.The optimal preparation process of fermented buffalo milk was:Lactobacillus reuteri starter:traditional starter 2:1,white sugar was added 3.00%,fermentation temperature was 40.00℃,and the sensory score of fermented milk was the highest(86.63±1.47),the number of live bacteria of Lactobacillus reuteri also reached 1.033×108 CFU/mL.This study provided an important theoretical and technical reference for the development and utilization of this strain.