Effects of high hydrostatic pressure, ultraviolet light-C, and far-infrared treatments on the digestibility, antioxidant and antihypertensive activity of α-casein.

Alpha-casein is the most important bioactive protein in processing technologies. This study investigated the digestibility, antioxidant and antihypertensive activities of α-casein when treated by high hydrostatic pressure (HPP), ultraviolet light-C (UV-C), and far-infrared radiation (FIR). The in vitro digestibility was modified after treatments, especially after 5min/200MPa HHP treatment. Ultra-performance liquid chromatography-tandem mass spectrometry analysis showed that one 5min/200MPa HHP treatment resulted in the highest yield of peptides. Based on the in vitro gastrointestinal digestion and antioxidant and antihypertensive activity assays, HHP increased the angiotensin converting enzyme inhibitory activity at different levels. The 15min UV-C treatment resulted in the highest antioxidant DPPH radical-scavenging activity, while the 15min UV-C and FIR treatments had higher angiotensin converting enzyme inhibitory and antioxidant activities than those of 5min treatments. This study revealed that HHP, UV-C and FIR treatments increased the antioxidant and antihypertensive activities of α-casein.