Antioxidant and antibacterial activities of bioactive peptides in buffalo's yoghurt fermented with different starter cultures.

The effect of 20552 ATCC (T2) or CH 5 (T3) in combination with yoghurt starter (1:1) on the antioxidant and antibacterial activities of the bioactive peptides present in buffalo's yoghurt was studied. The SDS-PAGE results indicate that all caseins were completely hydrolyzed by both strains, whereas whey protein fractions were still present. All starter cultures have the ability to produce low-molecular-weight bioactive peptides, most of which were originated from β-casein and fewer from αs casein. The antioxidant activity (%) of the water-soluble peptide extract from yoghurt samples increased in all samples during storage. Samples containing CH 5 showed the highest values. All yoghurt treatments displayed antibacterial activity against . Control yoghurt and T3 showed higher antibacterial activity on , and as compared to T2.