Assessment of antioxidant capacity by method comparison and amino acid characterisation in buffalo milk kefir

This study aimed to analyse the antioxidant capacity and total phenolic content of buffalo milk kefir fermented with grains or a commercial starter culture, as well as characterisation of the amino acid profile. During fermentation, the ferrous‐reducing activity of samples increased, while the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) scavenging activity decreased. The highest value of the ABTS and DPPH scavenging activity was recorded for buffalo milk kefir with grain, which also showed a lower ferric‐reducing antioxidant power during storage. Statistical analyses showed a significant effect of starter culture type and fermentation/storage time on the antioxidant capacity of buffalo kefir.