Optimization of Enzymatic Hydrolysis Conditions of Ovalbumin from Duck Eggs and Biological Activity of the Resulting Peptides

Abstract:

The enzymatic hydrolysis conditions of ovalbumin from duck eggs were investigated through orthogonal test, and the optimal hydrolysis conditions were determined by taking the hydrolysis degree as the index: the amount of papain 4.5×104 U/（g·min）, hydrolysis time 5.5 h, temperature 55 ℃, pH 6.40. With the optimal conditions, the hydrolysis degree was 27.91%. The molecular weight distribution ranges of hydrolysate were determined by HPLC: 0w<300(33.71%), 300w<450(29.21%), 450w<1 450(20.42%), 1 450w<6 500(0.49%), 6 50012 500(11.12%). Its biological activity was further studied. Hydrolysate (250 μg/mL) significantly increased the secretion of NO, cytokines TNF-α and IL-6 in RAW 264.7 cells (P<0.05), showing a certain immunological activity. Meanwhile, the inhibition rate of 1 000 μg/mL hydrolysate for AAPH induced erythrocyte hemolysis was （53.95±1.82）%(P<0.05), the scavenging rates of DPPH and ABTS+·free radical were （31.92±0.54）% and （86.46±2.12）%, and the ORAC value was 0.357 4 μmol/mg, indicating that the hydrolysate also had a good antioxidant activity in vitro.