Antioxidant and antimicrobial activity of camel milk casein hydrolysates and its fractions

• Enzymatically hydrolyzed camel milk casein was ultra-filtered for assessment of antioxidant and antimicrobial activity.
• Whole hydrolysates had significantly (P < 0.05) higher antioxidant and antimicrobial activity than their fractions.
• It was observed that α-Chymotrypsin could produce protein hydrolysates and fractions with higher antioxidant activities.
• Proteases such as Alcalase and α-Chymotrypsin could produce casein paptides with higher antimicrobial activity.

Camel milk casein hydrolysates by Alcalase, α-Chymotrypsin and Papain were ultra-filtered and different fractions were assessed for antioxidant and antimicrobial activity. The casein hydrolysate fractions were analyzed for antioxidant activities viz. 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing antioxidant power assay (FRAP), and antimicrobial activity by inhibition zone assay. In ABTS, DPPH and FRAP assay, the inhibition activity was recorded significantly (P < 0.05) higher for whole hydrolysares whereas among fractions F2 (1–5 kDa), F3 (5–10 kDa) of all the three hydrolysates had comperatively higher antioxidant activity. It was also observed that α- Chymotrypsin could produce protein hydrolysates and fractions with higher antioxidant activities. The antimicrobial activity (zone of inhibition; mm) was also recorded higher for whole hydrolysates as compared to their fractions; however, among different fractions the inhibition zones were almost comparable. It was also observed that Alcalase and α-Chymotrypsin could produce paptides with higher antimicrobial activity. The results suggested that camel milk casein hydrolysates could be fractioned to get specific molecular weight peptides, however, for food application or for direct human consumption, use of whole hydrolysates could be more beneficial with regards to its functionalities and cost of production.