Functionalized tea polyphenols in food: from design to application

Tea polyphenols (TPs) exhibit diverse bioactivities and are increasingly recognized as promising multifunctional components in advanced food systems. Owing to their unstable structures and low bioavailability, research focus has shifted from the direct application of individual TPs to the design of functionalized TPs complexes that co-assemble TPs with food matrices (e.g., proteins, polysaccharides, lipids, and minerals). This review systematically summarizes the molecular interaction mechanisms of functionalized TPs, including covalent and noncovalent interactions (e.g., hydrophobic interactions and metal coordination), and discusses how these interactions regulate the structural organization, physicochemical stability, and functional properties of functionalized TPs. We further highlight the enhanced functionalities of these complexes, including improved antioxidant and antimicrobial activity, stabilization of flavor compounds, nutrient protection, and improved bioavailability. Moreover, their applications in food preservation, structural modulation, and flavor enhancement are also summarized. Furthermore, we propose integrating machine learning and molecular simulation to systematically elucidate the molecular interaction mechanisms of functionalized TPs, thereby promoting the application of structure-oriented scalable industrial production. Overall, functionalized TPs complexes represent a pivotal approach to overcoming the limitations of free TPs, offering a robust foundation for their incorporation into next-generation functional foods and health-promoting products.