Antioxidant properties of kefir produced from different cow and soy milk mixtures

The aim of this study was to determine some antioxidant capacities of kefir samples produced from different cow/soy milk mixtures. Several antioxidative activities including the inhibition of ascorbate autoxidation, reducing activity, the scavenging effect of superoxide anion radicals and hydrogen peroxide were investigated. Kefirs produced from whole soymilk had the highest inhibition rate of ascorbate autoxidation. Reducing activities of kefir samples which were expressed as equivalent amounts of cysteine were found statistically different and elevated by increased soymilk ratio. The inhibition of superoxide radical generation results of cow, cow/soy and soymilk kefir samples were found to be statistically different. However, the effect of fermentation on this activity neither with kefir grain nor culture was significant. Results indicated that all of kefir samples were not exhibit a hydrogen peroxide scavenging activity.