Screening of antioxidative lactic acid bacteria from the intestinal tract of the longevity village people of Rugao

This study was undertaken to obtain lactic acid bacteria with high antioxidant properties which could be applied in functional foods.The radical scavenging capacity and reducing power of fermentation broth of 30 LAB isolated from the intestinal tract of the longevity village people of Jiangsu Rugao were studied, and the radical scavenging capacity, reducing power and antioxidant enzyme activities of different components of 4 strains with high antioxidant activity that were picked out through preliminary screening were also tested. The results showed that the antioxidant properties of fermentation broth of 4 strains were not equivalent to the sum of its each component, and antioxidant properties of fermentation supernatant was significantly higher than the cells and intracellular extracts.Finally, two strains L10 and L13 with high antioxidant activity were picked out. The hydroxyl radical scavenging activity of fermentation supernatants of L10 and L13 were 56.4% and 64.8%, respectively.While the DPPH radical scavenging activity were 51.8% and 53.5%, respectively. The reducing power of fermentation supernatants of L10 and L13 were 2.523 and 2.540, respectively. The T- SOD activity were 32.802U /mL and33.825U /mL, respectively.While the GSH- Px activity were 37.273U /mL and 45.012U /mL, respectively.L10 and L13were identified as Lactobacillus fermentum and Lactobacillus casei, respectively.