Reducing the allergenic capacity of beta-lactoglobulin by covalent conjugation with dietary polyphenols

To help produce hypoallergenic food, this study investigated reducing the allergenicity and improving the functional properties of bovine beta-lactoglobulin (beta LG) by covalent conjugation with (-)-epigallo-catechin 3-gallate (EGCG) and chlorogenic acid (CA). The covalent bond between the polyphenols and the amino acid sidechains in beta LG was confirmed by MALDI-TOF-MS and SDS-PAGE. Structural analysis by fluorescence spectroscopy, circular dichroism (CD) and Fourier transform infrared (FTIR) indicated that the covalent conjugate of EGCG and CA led to the changed protein structure of beta LG. Western blot analysis and enzyme-linked immunosorbent assay indicated that conjugation of beta LG with these polyphenols was effective in reducing the IgE-binding capacity of beta LG. The conjugates maintained the retinol-binding activity without denaturation the protein and enhanced the thermal stability with high antioxidant activity. The study provides an innovative approach to producing hypoallergenic food.