Effects of Lactic Acid Bacteria Fermentation on Hypoglycemic and Antioxidant Activities of Goat Yoghurt in Vitro

Objective: The effects of lactic acid bacteria on the hypoglycemic and antioxidant activities of fermented goat milk were studied. Methods: Three lactic acid bacteria with hypoglycemic and antioxidant functions preserved in the laboratory and commercial yoghurt starters Lactobacillus bulgaricus (LB) and Streptococcus thermophiles (ST) were used as strain starters. The goat milk was fermented by single strain fermentation and mixed fermentation with commercial starters. The antioxidant and hypoglycemic functions of goat yoghurt fermented by different lactic acid bacteria were analyzed in vitro. Results: The results showed that in vitro antioxidant and hypoglycemic activities of goat milk fermented by single and mixed fermentation were improved. The goat yoghurt fermented by Pediococcus acidilactici GC215 had the highest DPPH clearance rate and reducing activity, which were 87.35% and 359.17 μmmoL/L L-cysteine reduction equivalent respectively. And its PTIO free radical clearance rate was 11.25%. Compared with unfermented goat milk, the inhibition rate of α-glucosidase activity of goat milk fermented by Liquorilactobacillus mali L31 increased by 44.08%. The goat yoghurt fermented by Lactobacillus brevis PC-2 mixed with LB and ST had the highest inhibition on α-amylase activity, which the activity inhibition rate was 82.30%. Conclusion: Functional lactic acid bacteria fermentation of goat milk could improve the antioxidant and hypoglycemic activities of goat yogurt in vitro. The research results would provide reliable strain resources for functional fermentation of goat milk and a new direction for the development of functional products of goat milk at the same time.