降胆固醇和耐酸耐胆盐益生菌的筛选研究

本研究通过含有胆固醇胶束的MRS-胆固醇液体培养基从五株益生菌中筛选出降胆固醇能力较强的益生菌,接着对筛选出的益生菌进行耐酸、耐胆盐试验。结果表明,五株益生菌都有降胆固醇的功能,其中干酪乳杆菌LCA-1、鼠李糖乳杆菌LR-D和植物乳杆菌LP-C的胆固醇去除率较高,分别为25.26%、22.18%和20.03%;LR-D能够短时耐受低p H值环境,在p H 2.5的发酵液中培养2h的存活率能够达到14.39%,但是耐胆盐能力较差;LP-C能够长时间耐受低p H值的环境,具有较强的胆盐耐受能力,在高胆盐环境(0.5%)中培养2 h的存活率高达133.75%,培养24 h的活菌数仍保持在1.13×105 cfu/m L,此时其余两株菌的活菌未检出,说明LP-C能够耐受高胆盐环境。植物乳杆菌LP-C具有较高的胆固醇去除率,能够耐受低p H值和高胆盐环境。因此,可用于进一步研究与开发。

Screening of Cholesterol-reducing Probiotics and Its Acid and Bile Salt Tolerance

In this study, probiotics with strong cholesterol-lowering ability were screened from five probiotics by using MRS-cholesterol liquid medium containing cholesterol micelles, and the selected probiotics were tested for their acid and bile tolerance. The results demonstrated that all the five strains exhibited cholesterol-lowering function, with the Lactobacillus casei (LCA-1), Lactobacillus rhamnosus (LR-D) and Lactobacillus plantarum (LP-C) having higher cholesterol degradation rates (as 25.26%, 22.18% and 20.03% respectively). LR-D could tolerate a low pH environment for a short time period but exhibited poor bile salt tolerance, with a survival rate of 14.39% after a 2 h culture in the fermentation broth at pH 2.5. LP-C could tolerate a low acid environment for a long time period and exhibited strong bile salt tolerance, with a survival rate of 133.75% and the viable cell number of 1.13×105 cfu/mL after being cultured in high bile salt medium (0.5%) for 2 h and 24 h, respectively. In these cases, the other two strains remained undetected. These results indicated that LP-C could tolerate the high bile salt environment. LP-C possessed a high cholesterol-removing rate and could withstand a low pH and high bile salt environment. Therefore, this probiotic can be used for further research and development.