关键词: 六堡茶；乳酸菌；多样性；降胆固醇；胃肠耐受

Abstract: To explore the diversity of lactic acid bacteria (LAB) during the pile fermentation process of Liupao tea and screen for cholesterol-reducing strains for use as probiotics in preventing hyperlipidemia caused by unbalanced diets, high-throughput sequencing combined with pure culture was used to analyze the bacterial diversity at different stages of fermentation, and the cholesterol-lowering capability and gastrointestinal tolerance in vitro of vigorously growing strains were evaluated. The results showed that four genera (Lactobacillus, Weissella, Lactococcus and Enterococcus) and five species of LAB were detected from 25 samples with Lactobacillus being the single dominant genus. A total of 76 strains were isolated, including 55 Lactobacillus pentosus, 3 Enterococcus casseliflavus, 5 Weissella paramesenteroides, 8 Weissella hellenica and 5 Lactococcus taiwanensis. In addition, the rate of cholesterol removal by the selected strains ranged from 0% to 30%, and Lactobacillus pentosus strain L131 gave the highest removal rate of (29.56 ± 0.37) %. The survival rate of this strain was (92.70 ± 0.71) % and (77.54 ± 4.81) % in artificial gastric juice (pH 3.0) and artificial pancreatic juice (pH 8.0), respectively, significantly higher than that of other strains (P < 0.05). The results of this study will provide a theoretical basis for the development of healthy dark tea products and probiotics from tea.

Key words: Liupao tea; lactic acid bacteria; diversity; cholesterol-lowering; gastrointestinal tolerance