Physicochemical properties and antioxidant activity of water-soluble protein ( peptide) during incubation of fertilized eggs

Fertilized eggs of Sanhuang chicken were selected as raw materials and the change of the content of moisture, ash, crude fat, protein, and polypeptide as well as pH and the antioxidant activity of water-soluble protein ( peptide) were researched in the incubation period.The result showed that the content of moisture and fat and the pH of egg white presented an upward trend during the incubation, while the content of ash, protein and polypeptide and the pH in yolk showed an increasing trend, in addition, the water- soluble protein ( peptide) had strong antioxidant activity, and a positive correlation between the antioxidant activity and the sample concentration.In the 15d of the incubation, the sample had the strongest scavenging activities on DPPH radical.Moreover, when the concentration was 5mg /mL, the scavenging rate reaches 90.68%.The 12 and 15d samples had the strongest capability to remove ·OH, when the concentration was 10mg /mL, the scavenging rate was 70.09% and 70.31%respectively. Besides, the antioxidant capacity of the 6d ample enhanced significantly with the increasing concentration of sample. When the concentration was 5mg /mL, the light absorption value of the 6d sample was1.53, at the wavelength of 695nm, and significantly higher ( p < 0.01) that other days. However, when the concentration was 10mg /mL, the total antioxidant abilities of the 3, 6, 9, 12 and 15d samples had no significant differences ( p > 0.05) , while all were significantly higher than the 0d sample's.The study could provide a reference for the research of the development of new natural safe antioxidant.