降胆固醇乳酸菌的筛选及其益生元干预生长作用分析

本研究从传统自然发酵的酵素饮品中分离筛选出一株高效降胆固醇菌株,该菌株具有较好的胆盐耐受性和耐酸能力。在pH3的酸性环境下,耐酸率为71.53%,该菌株能够长时间耐受胆盐环境,培养16h的胆盐耐受率为42.09%。以二甲苯为吸附剂,疏水率为35.91%,有较好的黏附特性;益生元不仅能够促进菌株生长,而且可显著提高降胆固醇能力。4种益生元中乳果糖促进生物量增加幅度最大,培养至16 h时生物量达到最高。乳果糖对菌株产酸性能影响最显著,pH值可降至3.56,胆固醇去除率达41.10%。该菌株对菊粉的利用率低,说明菌株对不同益生元具有选择性代谢。菌株经形态学观察和16S rDNA鉴定为副干酪乳杆菌,并命名为Lactobacillus paracasei S0940。本研究为进一步研究体内降脂能力以及开发功能性乳酸菌食品提供理论依据。

Screening of Cholesterol-Lowering Lactic Acid Bacteria and the Effects of Prebiotics on Their Growth

In this study, a highly effective cholesterol-lowering strain was isolated from traditional naturally fermented drinks with high bile salt and acid tolerance. In the acid environment with a pH of 3, the acid resistance rate was 71.53%. The strain could tolerate bile salt for a long time with the tolerance rate of 42.09% after exposure for 16 h. With xylene as the adsorbent, the hydrophobicity of the strain was 35.91%, indicating good adhesion characteristics. The prebiotics not only promoted the growth of the strain, but also improved significantly the cholesterol-lowering ability. Among the four prebiotics, lactulose promoted the greatest increase of the biomass, and the biomass reached the highest level after 16 h. Lactulose exerted the greatest effect on the acid production, with the pH value decreasing to 3.56 and cholesterol removal rate reaching 41.10%. Inulin was poorly utilized by the strain, indicating that the strain exhibited selective metabolism to different prebiotics. Based on morphological observations, the strain was identified Lactobacillus paracasei, named Lactobacillus paracasei S0940. This study provides a theoretical basis for further study of cholesterol-lowering ability in vivo and the development of lactic acid bacteria-containing functional foods.