Physical, chemical and biochemical properties of casein hydrolyzed by three proteases: partial characterizations.

Sodium caseinate (NaCas) was hydrolyzed by papain, pancreatin and trypsin from 10 min to 24h, and the hydrolysates were partially characterized for several important properties. At the studied conditions, papain and trypsin were more effective in hydrolyzing NaCas than pancreatin. Pancreatin treatments showed an initial increase in surface hydrophobicity, contrasting with the consistent decrease for the other two treatments. The solubility of NaCas at acidic pH was improved, becoming pH-independent after 24h hydrolysis. The emulsifying properties generally showed improvements after hydrolysis. The DPPH free radical scavenging activity, reducing power, and inhibition of linoleic acid autoxidation were significantly enhanced after appropriate hydrolysis, while metal ion chelating effects were slightly attenuated. The angiotensin converting enzyme-inhibitory activity was significantly improved by up to 9 times than that of NaCas. These findings indicate that physical, chemical and biochemical properties of casein hydrolysates can be improved by selecting proteolytic conditions to produce functional ingredients.