Research Of Procyanidins On Covalent Conjugation Application In Modification Of Egg White Protein

In this study,ovalbumin(OVA),ovomucoid(OVM)and procyanidin(PC)were used as raw materials to promote the covalent binding between proteins and polyphenols through covalent coupling under alkaline conditions.The macroscopic and microscopic structures of covalent complexes were characterized by traditional spectroscopy.Indirect competitive ELISA(Ig E /Ig G binding ability),KU812 cell degranulation test(release of cytokines)and were used to analyze the change of protein sensitization ability;The functional characteristics of the protein before and after covalent modification were evaluated,and the preparation of high antioxidant protein was optimized.The final conclusions are as follows:(1)The molecular weight of the covalent complex(OVA-PC and OVM-PC)increased,the contents of free amino group and free sulfhydryl group decreased to some extent,indicating the occurrence of covalent binding of polyphenols and protein;(2)After covalent modification with PC,the structure of OVA and OVM will be affected by them.Among them,The increase of ?-helix content and irregular curl showed that the secondary structure of protein tended to be stable;The results show that the three-stage structure of the two covalent complexes has changed significantly;(3)The binding ability of Ig G and Ig E of OVA-PC and OVM-PC was decreased significantly,and the binding ability of Ig G and Ig E in the control group was also decreased;(4)After the degranulation of KU812 cells induced by PC covalently modified OVA and OVM,the production of the ?-Hex?Anti tumor necrosis factor(TNF-?)?The contents of human interleukin(IL-4,IL-6)and histamine were decreased in varying degrees,which indicated that the potential allergenicity of covalent complexes OVA-PC and OVM-PC was lower than that of the original protein;(5)The surface hydrophobicity and hydrophilicity of the covalent complexes of ova and OVM were weakened and hydrophilicity was enhanced;The average particle size of the particles increased;The emulsification,foaming and anti-oxidation ability of the system were improved to different extent;(6)Through single factor and orthogonal test,the DPPH free radical scavenging ability of covalent complex was compared in four aspects: the addition ratio of OVA and PC,p H value of reaction solution,reaction time and reaction temperature.The best preparation technology was obtained,namely: the mass ratio of OVA to PC was 5:1,p H 9.0 and reaction time was 24 h.at this time,the antioxidant capacity of protein samples was the strongest.