Antioxidative effect of yak milk caseinates hydrolyzed with three differenct proteases

Abstract

Aim: Yak milk is a type of milk that people are less familiar with due to its remote geographical location which may have significant effects on composition, microbiota and hydrolytic outcome. Present work was designed with the aim to evaluate the antioxidative effect of peptides derived from yak milk caseinate on hydrolysis with three different proteases. Materials and Methods: In this investigation Yak milk casein was hydrolyzed by three commercially available proteases (Trypsin, Pepsin and chymotrypsin). These hydrolysates collected at different hydrolysis times (30 min, 60 min, 90 min, 120 min, 150 min, 180 min, 210 min, 240 min, 270 min, 300 min, 330 min and 360 min) were assayed for their antioxidant activity with respect to the effect of incubation period. Results: Among all the enzyme hydrolysates, the tryptic hydrolysates showed highest antioxidant activity followed by chymotryptic hydrolysates. Further, the peptide samples showing highest activity were subjected to RP-HPLC for their partial characterization. Tryptic and peptic hydrolysates produced peaks mainly in the region of hydrophillic solvent indicating the presence of hydrophillic peptides/peptides. Conclusion: The results indicated that yak milk casein could be a resource to generate antioxidative peptides and be used as multifunctional active ingredients for many value-added functional foods as well as a traditional food protein.