Investigation of the effect of probiotic supplementation on the antioxidant activity of homemade yogurt

Probiotics have been defined as "live microbial food supplements or bacterial components that have been shown to have positive effects on human health". Lactobacillus and Bifidobacterium species are commonly used probiotic bacteria. These bacteria have antioxidant, anti-inflammatory and anticancer properties as well as providing gastrointestinal balance. In this study, in order to investigate the effect of probiotic supplementation on the antioxidant activity of homemade yogurt, total phenolic compounds, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and ABTS [2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid)] radical cation scavenging activities, FRAP (ferric-reducing antioxidant power) and β-glucosidase activity of the control and probiotic yogurts were determined. All antioxidant and enzyme activity values of probiotic yogurt samples were found to be higher than the values of control yogurt. With the increase in the amount of probiotics, a dose-dependent increase in yogurt activities was determined. During 1 week period storage at 4˚C, all activities of yogurt samples were generally observed to decrease. It was concluded that probiotic supplementation has an enhancing effect on the antioxidant activity of homemade yogurt and that therefore probiotics may have positive effects on human health.