Comparative Evaluation of the Structures and Properties of Hydrothermally Produced Corn Starch‐Hydroxycinnamic Acid Complexes

ABSTRACT Despite extensive investigations into the role of phenolic acids in modulating starch digestion, the structure–function relationships contributing to alterations in the profiles of starch‐phenolic acid complexes remain unresolved. In this study, we explored the structures and digestibility of hydrothermally produced starch‐hydroxycinnamic acid complexes. The multi‐scale characterization of the structures of these complexes, along with the molecular dynamics simulation results, indicates that hydroxycinnamic acids with a larger molecular radius, longer molecular chain length, and more methoxy groups facilitate the formation of V‐type starch‐hydroxycinnamic acid inclusions. Conversely, hydroxycinnamic acids with a high number of hydroxyl groups and a large molecular radius would impede starch retrogradation. Furthermore, hydroxycinnamic acids with chain lengths shorter than 12 Å are unable to form stable V‐type starch‐hydroxycinnamic acid complexes. The ordered structures of these complexes, combined with the inhibitory effects of hydroxycinnamic acids on amylolytic enzymes, significantly influence starch digestibility. As a result, corn starch complexed with chlorogenic acid exhibited a highly ordered structure (crystallinity of 5.47%) and a resistant starch content of 26.42% compared to other hydroxycinnamic acid complexes. These findings underscore the controllable role of phenolic acid molecular sizes, aside from their functional groups, in modulating both the structures and digestibility of starch.