The structural and functional properties of hemp protein isolate-epigallocatechin-3-gallate biopolymer covalent complex during heating

BACKGROUNDIt is well known that hemp proteins have the disadvantages of poor solubility and poor emulsification. To improve these shortcomings, an alkali covalent cross-linking method was used to prepare hemp protein isolate-epigallocatechin-3-gallate biopolymer (HPI-EGCG) and the effects of different heat treatment conditions on the structure and emulsifying properties of the HPI-EGCG covalent complex were studied.RESULTSThe secondary and tertiary structures, solubility, and emulsification ability of the HPI-EGCG complexes were evaluated using particle size, zeta potential, circular dichroism (CD), and fluorescence spectroscopy indices. The results showed that the absolute value of zeta potential of HPI-EGCG covalent complex was the largest, 18.6 mV, and the maximum binding amount of HPI to EGCG was 29.18 mu mol g-1. Under heat treatment at 25-35 degrees C, the alpha-helix content was reduced from 1.87% to 0%, and the beta-helix content was reduced from 82.79% to 0% after the covalent binding of HPI and EGCG. The solubility and emulsification properties of the HPI-EGCG covalent complexes were improved significantly, and the emulsification activity index (EAI) and emulsion stability index (ESI) were increased by 2.77-fold and 1.21-fold, respectively.CONCLUSIONA new HPI-EGCG covalent complex was developed in this study to provide a theoretical basis for the application of HPI-EGCG in food industry. (c) 2023 Society of Chemical Industry.