The structural and functional properties of HPI‐EGCG covalent complex during heating

ABSTRACT BACKGROUND It is well known that hemp proteins have the disadvantage of poor solubility and emulsification. In order to improve these shortcomings, we used an alkali covalent cross‐linking method to prepare hemp protein isolate‐epigallocatechin‐3‐gallate biopolymer (HPI‐EGCG) and studied the effects of different heat treatment conditions on the structure and emulsifying properties of the HPI‐EGCG covalent complex. RESULTS The secondary and tertiary structures, solubility, and emulsification ability of the HPI‐EGCG complexes were evaluated by particle size, zeta potential, 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 μmol/g. Under the heat treatment condition of 25‐35°C, the content of α‐helices was reduced from 1.87% to 0%, and the content of β‐helices 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 significantly improved, and the emulsification activity index (EAI) and emulsion stability index (ESI) were increased by 2.77‐fold and 1.21‐fold, respectively. CONCLUSION A new covalent complex of HPI‐EGCG was developed in this study to provide a theoretical basis for the application of HPI‐EGCG in food industry. This article is protected by copyright. All rights reserved.