Abstract: Glycinin was isolated from defatted soybean meal by alkali solubilization and acid precipitation method in this study. The antigencity of glycinin was determined by indirect competitive enzyme-linked immunosorbent assay (ELISA) and investigated as a function of pressure, pressurization time and glycinin concentration. The immunogenicity and structural characteristics were analyzed after high hydrostatic pressure treatment. The indirect competitive ELISA showed that high hydrostatic pressure treatment could significantly affect the antigenicity of glycinin. The results of immunoblotting showed that the immunogenicity of glycinin was reduced but not completely eliminated after the treatment. Fourier transform infrared spectroscopy showed that the contents of α-helix and β-sheet in the treated sample decreased whereas β-turn and random coil increased. Non-reduced electrophoresis and fluorescence spectroscopy demonstrated that the spatial structure of glycinin was depolymerized and the hydrophobic amino acid residues were exposed on the surface of the protein. Moreover, its tertiary and quartenary structures were destroyed. The change in the spatial structure of the protein may mask its antigenic epitopes, thereby reducing its antigenicity.

Key words: glycinin, high hydrostatic pressure, antigenicity, structure