Effects of OSA-starch-fatty acid interactions on the structural, digestibility and release characteristics of high amylose corn starch

This study investigated the effects of octenyl succinic anhydride (OSA)-starch-fatty acid (FA) interactions on the structural, digestibility and release characteristics of high amylose corn starch (HAS). FTIR and XRD analysis showed that the hydrophobic interaction between HAS and FA promoted the covalent binding between OSA and HAS. With the increasing of the FA chain length, the complex index, degree of substitution, R1047/1022 and relative crystallinity of OSA-HAS-FA increased first and then decreased, whereas the first-order rate coefficient and percentage of digested in infinite time showed an opposite trend. Structural changes and the molecular interactions of OSA-HAS-FA with 12‑carbon FA resulted in highest resistant starch content (45.43%) and encapsulation efficiency of curcumin (Cur) (47.98%). In vitro release test revealed that Cur could be gradually released from OSA-HAS-FA in simulated gastric, intestinal and colonic fluids. Results provided novel insights into HAS-FA complex grafted with OSA as carrier for colon-specific of functional materials. OSA-starch-fatty acid molecular interactions alter the structural, digestibility and release characteristics of starch. [Display omitted] •Hydrophobic interaction of HAS-FA promoted covalent binding of OSA-HAS in OSA-HAS-FA.•Interaction between OSA, HAS and LA was the strongest.•Interactions of OSA-HAS-FA enhanced V-type crystalline with compact granule surface.•OSA-HAS-FA interactions improved the anti-digestibility and release properties of HAS.•OSA-HAS-FA controlled release of Cur in SGF, SIF and SCF for colon-specific delivery.