Chemically modified starch-polyphenol interactions: mechanisms, influencing factors, characterization, and...

Chemically modified starches (CMS) constitute a versatile class of biopolymers with tailored functional properties. However, their performance in complex food systems remains constrained by strict regulatory limits on the degree of substitution (DS) and the non-uniform distribution of functional groups across the starch matrix. Natural polyphenols, a diverse group of bioactive compounds characterized by abundant phenolic hydroxyl groups and aromatic ring structures, represent a promising strategy for enhancing CMS functionality. CMS interacts with polyphenols via non-covalent bonds (e.g., hydrogen bonding, hydrophobic interactions, and electrostatic interactions) or covalent bonds. These interactions modify the CMS structure and improve its emulsifying capacity, colloidal stability, film-forming ability, anti-retrogradation performance, and resistance to digestion. Notably, different types of CMS, including esterified, etherified, and oxidized derivatives, exhibit distinct interaction behaviors with polyphenols, which are governed by the degree of substitution, botanical starch source, polyphenol molecular architecture, and environmental conditions such as pH, temperature, and ionic strength. The resulting synergistic systems have found diverse applications in functional delivery platforms (emulsions and encapsulation), food texture modification, as well as in active and intelligent packaging. This narrative review provides a comprehensive examination of the driving forces, interaction mechanisms, characterization techniques, key regulatory factors, and functional applications of CMS-polyphenol complexes. Theoretical insights derived from this literature synthesis are intended to inform rational design strategies for constructing CMS-based functional materials with enhanced multifunctionality and tunable physicochemical properties.