Structure,Composition Analysis and Functional Activity of Duck Egg Ovalbumin

In this study,three extraction methods of duck egg ovalbumin were compared. Firstly,the secondary structure was analyzed by Fourier infrared spectroscopy,circular dichroism and electron microscopy. The nutrition evaluation was carried out by semi-automatic amino acid analyzer. Finally,the RAW 264.7 cell model and DPPH·,ABTS⁺· and ORAC antioxidant models were used to explore their immunomodulatory and antioxidant activities,respectively. The experimental results showed that the total nitrogen content of the protein obtained by pH4.50 and 60% saturated ammonium sulfate precipitation was 86.75%±4.12%,and the protein yield was 86.17%±2.69%. Structural analysis showed that α-helix accounted for 15.06%,β-sheet accounted for 24.69%,β-turn angle accounted for 25.63%,and random coli accounted for 33.83%,which showed the structure of general albumin. The functional activity model showed that it could significantly increase the secretion of NO,TNF-α and IL-6 in the supernatant of RAW 264.7 cells(P<0.05),showing immunomodulatory activity. In vitro antioxidant activity showed that when the concentration of ovalbumin was 2000 μg/mL. ABTS⁺· scavenging rate was 57.05%,DPPH free radical scavenging rate was 26.12%,ORAC value was 0.3148 μmol/L TE/mg,showing certain antioxidant activity,providing theoretical support for the basic research of egg albumin in duck eggs.