Modification of Inca peanut albumin-polyphenol conjugates by chitosan through laccase catalysis: Structural, interfacial, and functional properties.

As a green method, enzyme crosslinking can catalyze chitosan (CS) to improve further the structural, interfacial, and functional properties of Inca peanut albumin (IPA)-polyphenols. However, the structural impact of laccase-catalyzed CS on different IPA-polyphenol conjugates has not been reported. Results revealed that enzymatic cross-linking of IPA-gallic acid (GA) and IPA- (-)-epigallocatechin-3-gallate (EGCG) with CS resulted in a decrease in α-helices, an increase in β-helices, and a more ordered structure. The contact angles of IPA-GA-CS and IPA-EGCG-CS decreased from 99.4° and 101.2° to 89.9° and 95.4°, respectively, indicating reduced hydrophobicity and enhanced interfacial adsorption. Furthermore, using copolymers as emulsifiers significantly improved the emulsification and antioxidant properties of high internal phase Pickering emulsions (HIPEs). In particular, the apparent viscosity and viscoelasticity of HIPEs constructed with IPA-GA-CS notably improved, and the EGCG-induced copolymers exhibited superior lipid antioxidation. The method of laccase-mediated crosslinking for the preparation of protein-polyphenol-polysaccharide polymers enhances the functional properties and anti-pH sensitivity of IPA, representing a novel protein modification strategy.