Construction of OSA-starch and caffeic acid composite system driven by high pressure homogenization: Multiscale structural evolution and digestibility regulation mechanism

The effect of modification treatments on the structure and function of starch-polyphenol complexes has become a hot research topic. Therefore, this study aims to systematically investigate the structural reorganization and digestibility modulation of octenyl succinic anhydride modified rice starch (OR)-caffeic acid complexes (ORCA) under gradient high pressure homogenization (HPH) pressures (50, 80, and 110 MPa). HPH promoted the interaction between starch and CA compared to the non-HPH-treated samples. Among the HPH-treated samples, ORCA exhibited more complete granular structures and higher thermal stability (311.65 °C) than the rice starch-CA complexes (RCA). Dual modification significantly improved resistant starch content. The underlying mechanism by which ORCA and HPH treatments regulated starch digestibility involved HPH-driven structural reorganization, which promoted the formation of a new densely ordered structure and crystalline barrier. This study provides theoretical support for the design of starch-based functional foods with anti-digestive properties.