Enzyme‐Assisted Covalent Modification of Apostichopus japonicus Body Wall Protein for Stabilizing High Internal Phase Emulsions: Enhancing Thermal Stability and Protection of Bioactive Compound

In this study, a novel high internal phase emulsion (HIPEs) stabilization strategy was developed by enzymatic modification of Apostichopus japonicus ( A. japonicus ) body wall protein (AJBWP) with (−)‐epigallocatechin gallate (EGCG), a process catalyzed by polyphenol oxidase (PPO). For the first time, stable HIPEs were prepared through the enzymatic covalent crosslinking of marine‐derived AJBWP with the plant polyphenol EGCG. EGCG catalyzed by PPO increased the contact angle of AJBWP to 80°, and enabled successful formation of an emulsion system exhibiting high elasticity and small droplet size (average particle size 9 μm). This system maintained good stability under extreme conditions (centrifugation at 7000 rpm, heating at 50°C) and achieved protection of fucoxanthin (FX). The green enzymatic modification technology proposed in this study provides a scalable solution for the high‐value utilization of by‐products from marine processing, demonstrated potential applications in the fields of functional food and drug delivery.