The influence of gamma irradiation on the immunoreactivity of gliadin and wheat flour

Abstract

The gliadin fraction of wheat flour gluten is potentially responsible for an allergic reaction in individuals with a genetic predisposition to allergy. In order to study the influence of ionising radiation on the immunogenicity of gliadin, samples of commercial gliadin powder and wheat flour were irradiated with doses between 2.2 and 12.8 kGy. Ethanolic extracts (40% ethanol/water, v/v) of treated samples were analysed by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies against ω-gliadin or polyclonal anti-gliadin antibodies and by immunoblotting after polyacrylamide gel electrophoresis. Irradiated gliadin samples show the increase in allergenicity measured by ELISA. A linear relationship between the immune response induced by irradiated gliadin and the applied radiation dose was observed. The increase in immunoreactivity was confirmed by immunoblot assays with sera containing anti-gliadin antibodies. Immunoreactivity of gliadin extracted from irradiated wheat flour was higher than the immune response of pure gliadin irradiated with the same dose. RP-HPLC was applied for the analysis of gliadin constituents after irradiation. The content of ω-gliadins in irradiated samples decreased with increasing radiation dose.