Effect of High Pressure Treatment on Antioxidant Activity of Casein Hydrolysates

The effects of high pressure treatment on enzymatic hydrolysis of casein hydrolyzed by trypsin and antioxidant activities of protein hydrolysates were investigated.Based on our measured data of hydrolysis (DH), DPPH radical, superoxide anion radical, hydroxyl radical scavenging activities and reducing power, we studied the hydrolysates and antioxidant activities as resulting from the high-pressure treatment of enzymatic hydrolysis of casein, trypsin, with and without the addition of casein to each and all of them.The results show that the high pressure treatment has a better effect on casein than on trypsin in terms of the DH which increases by 31.14% under the optimal condition of 200 MPa for 20 min, while the treatment effect is not as satisfactory for casein-trypsin mixture.In cases of DPPH and hydroxyl radical scavenging activities, the high pressure has a greater effect on trypsin compared with that on casein under 100 MPa/15 min or 50 MPa/5 min.Besides, the hydroxyl radical scavenging activity of casein treated at 150 MPa for 10 min and the reducing power of casein-trypsin mixture processed under 150 MPa for 15 min increase more markedly.Moreover, no correlation has been found between the antioxidant activities of the hydrolysates and their enzymatic properties.