Modification of β-lactoglobulin by glycation, high-pressure microfluidization and EGCG binding: Enhanced emulsifying...

To address the limitations of the low emulsifying and antioxidant properties of natural β-lactoglobulin (β-Lg), this study employed a multistep modification strategy involving konjac oligo-glucomannan (KOG) glycation, high-pressure microfluidization (HPM) treatment, and (-)-epigallocatechin-3-gallate (EGCG) covalent binding to systematically investigate its effects on the structure and function of β-Lg, as well as to elucidate the underlying regulatory mechanisms. Results showed that glycation led to the binding KOG to free amino groups on β-Lg, hindering the formation of covalent bonds with EGCG. Conversely, HPM induced β-Lg unfolding-refolding by disrupting intramolecular hydrogen bonds and regulating hydrophobic interactions, resulting in a 48.4% increase in EGCG binding capacity. Multistep modification led to an increase in the α-helix content, a decrease in the β-sheet content, and a reduction in the fluorescence intensity of β-Lg. Moreover, the emulsifying and antioxidant properties of β-Lg exhibited an increase by 8.9-99.3% and 10.5-810.1%, respectively. This study provides a novel strategy for the development of protein emulsifiers with both excellent emulsifying and antioxidant properties.