Antigenicity and structural properties of soybean protein-glucose conjugates

Abstract

Soybean is a high-quality protein source and one of eight major food allergens. Glycation is an effective way to remove protein allergens. In this paper, soy protein isolate(SPI) and glucose were used as raw materials for Maillard reactions, which were performed with various protein to carbohydrate ratios, temperatures, and experimental time, to prepare glycated conjugates. The inhibition of antigen β-conglycinin in SPI-glucose conjugates was used as an indicator, and indirect competitive enzyme-linked immunosorbent assay(ELISA) was employed to measure the antigenicity of glycated conjugates. When the mass ratio of protein to sugar was 3:1 at a temperature of 55, the antigenicity of the prepared glycated conjugates was relatively low. When the reaction time was 72 h, the inhibition rate of antigen β-conglycinin decreased from 93.54% to 22.58%. The Maillard reaction was confirmed by the trinitrobenzene sulfonic acid(TNBS) method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE). Changes in protein structure were studied by ultraviolet scans and Fourier transform infrared spectroscopy(FT-IR). These basic studies might provide research methods and a theoretical basis for determining the mechanism mediating the effect of glycation on antigenicity and developing soy protein products with low allergen contents.