Effects of high hydrostatic pressure combined with heat treatment on the antigenicity and conformation of β-conglycinin

Abstract

Soybean protein is considered as a main food allergen. This study illustrates the effects of a combination of high hydrostatic pressure (HHP) with heat treatment on soybean protein allergen. The main allergic protein β-conglycinin was isolated from low-temperature defatted soybean meal by the alkali-soluble acid precipitation method. The antigenicity and structure of β-conglycinin treated by HHP combined with heat treatment were analyzed by enzyme-linked immunosorbent assay (ELISA), western blot, non-reduced SDS-PAGE, Fourier transform infrared spectroscopy (FTIR), and fluorescence spectra. The antigenicity and immunogenicity of β-conglycinin was reduced significantly after HHP combined with heat treatment. Compared with the untreated protein, the antigenicity of β-conglycinin was lower, and it was reduced by 87.04% at 400 MPa and 100 °C for 20 min. The secondary structure of β-conglycinin changed after the combined treatment. The contents of α-helix and β-sheet decreased, but the contents of β-turn and random coils increased. The structure of the protein changed from order to disorder. Fluorescence spectroscopy showed that β-conglycinin exposed more hydrophobic groups after the combination treatment. HHP combined with heat treatment reduced the antigenicity of β-conglycinin by changing its conformation.