青藏高原牦牛酸奶中具高抗氧化能力乳酸菌的筛选

研究了从青藏高原牦牛酸奶中分离的881株乳酸菌的H2O2耐受能力,从中筛选出了8株对H₂O₂具有较强耐受能力的乳酸菌,并对它们清除DPPH自由基、OH自由基、O₂^-自由基的能力以及T-AOC活性做了进一步研究。结果显示,乳酸菌对DPPH自由基的清除能力都是活细胞体高于无细胞提取物;而在对OH自由基、O₂^-自由基的清除和T-AOC活性上恰好相反。菌株BX62、XS40和XM5在对自由基的清除中表现突出,在菌体浓度为10⁹ CFU/m L时,BX62的活细胞体对DPPH自由基的清除率最高（33.53%）,其无细胞提取物对O₂^-自由基的清除率同样最高（48.85%）。而在乳酸菌无细胞提取物对OH自由基的清除中XS40表现最好（52.12%）。此外,3株乳酸菌都具有较强的T-AOC活性。经16S r RNA鉴定和系统进化分析,3株菌分别为Lactobacillus parplantarum BX62,Lactobacillus plantarum XM5和Pediococcus acidilactici XS40。本研究从青藏高原牦牛酸奶中筛选的3株乳酸菌的确具有高抗氧化活性,有作为天然抗氧化剂的应用前景。 

Screening of lactic acid bacteria with high antioxidant capacity in Tibetan Plateau yak yogurt

The H₂O₂-resistant capacity of 881 strains which isolated from yak yoghurt in the Qinghai Tibet Plateau was introduced in this paper and 8 strains were screened out. It was also studied the scavenging abilities on DPPH radical,OH radical,O₂^- radical and total antioxidant capacity. The results showed that intact cells of lactic acid bactera scavenged the DPPH radical were more significantly than cell-free extracts while the opposite to clean up OH radical,O₂^- radical and total antioxidant capacity. According to the data,strains BX62,XS40 and XM5 had outstanding performance in the scavenging of free radicals. The intact cells of BX62 showed the highest ability to scavenge DPPH free radical(33.52%) at the concentration of 10~9CFU/m L. Besides its cellfree extracts also had the best scavenging ability on O₂^-radical(48.85%). While the cell-free extracts of XS40 showed the highest ability to scavenge OH radical(52.12%). In addition,3 strains also had higher T-AOC activity. 3 strains screened out in this paper were Lactobacillus parplantarum BX62,Lactobacillus plantarum XM5,and Pediococcus acidilactici XS40 by 16 S r RNA identification and phylogenetic analysis. In this study,3 strains of lactic acid bacteria screened out from yak yogurt in the Qinghai Tibet Plateru really had high antioxidant activity,which would have an application prospect as a natural antioxidant in the future.