Screening and Identification of Lactic Acid Bacteria with Antioxidant and Probiotic Properties from Qula and Fermented Milk in Tibet

This study isolated and identified lactic acid bacteria from the fermented milk and Qula in Tibet, through antioxidant indicators of anti-hydrogen peroxide and scavenging free radicals and probiotic properties of resistance to acid and bile salt. The results showed that 62 strains of bacteria were acquired, and 23 strains of them were tolerant to 0.3% hydrogen peroxide. Among the 23 strains, 4-C, 5-D, 5-E and 9-E had the highest scavenging capacity of DPPH·and·OH, with the rate of 86.97%±0.11% and 27.62%±0.28% respectively. The strains of 5-D, 5-E, 9-E and 4-C were identified as Lactobacillus delbrueckii subsp. Jakobsenii, Lactobacillus delbrueckii subsp. Jakobsenii, Lactobacillus gasseri, Pediococcus pentosaceus respectively. In addition, the 5-D and 5-E had the capability of concurrently antioxidant and probiotic properties of high tolerance to acid-base and 0.3% bile salt stress. They had enormous potential in the research and development of natural antioxidants, as well as enriched the excavation of lactic acid bacteria resources of traditional yak dairy products in Tibet area.