Impact of γ-radiation on antigenic properties of cow's milk β-lactoglobulin

This study evaluated the effects of gamma-radiation on the antigenic properties of beta-lactoglobulin in cow's milk. Liquid and lyophilized samples of cow's milk and whey were irradiated with gamma-cells (Co-60) at dose levels of 3, 5, and 10 kGy, at room temperature in the presence of air. Effects of treatment on proteins were monitored by Lowry's method, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and enzyme-linked immunosorbent assay. Radiation did not affect the molecular-weight distributions of proteins, but it did reduce their solubility. Furthermore, results showed that irradiation at 10 kGy increased the recognition of milk and whey powders by anti-beta-lactoglobulin (beta-Lg) rabbit immunoglobulin G, with the other samples remaining antigenically stable. These results indicate that gamma-rays do not reduce cow's milk beta-lactoglobulin antigenicity.