Research Progress on Protein–Polyphenol Interaction Mechanisms and Structure–Activity Relationship Modified by Physical Fields

Due to limitations in stability, solubility, and functional properties, natural proteins often fail to meet the demands of industrial production. Traditional chemical or enzymatic methods for protein modification suffer from high costs and the generation of numerous byproducts. In contrast, physical techniques offer a new approach to the green modification of macromolecules by inducing structural changes in proteins. Based on these techniques, the construction of protein–polyphenol composite systems is considered an effective strategy for enhancing food quality. This article systematically reviews the molecular mechanisms by which physical fields regulate protein–polyphenol interactions, summarizes how physical techniques improve the functional properties of composite systems and their applications in food, and aims to provide theoretical support for the development of novel functional food ingredients and their industrial applications.