Effect of high-power ultrasonication and heat treatments on the physicochemical properties of wheat starch–caffeic acid complexes

This study aimed to evaluate the interaction between wheat starch (WS) and caffeic acid (CA) by ultrasound (US) treatment at 75 °C for the formation of complexes while investigating the potential effects of structure, morphology, physicochemical properties, and digestion of WS-CA complexes. This study indicated that, following 30 s of ultrasonic treatment, the RS content of the WS-CA complex was significantly higher than that of all other treatment groups ( p < 0.05), reaching 18.84 g/100 g. The study identified starch particles that exhibited surface depressions, which were crucial in enhancing solubility and the release of amylose. These US-treated WS-CA complexes exhibited partially pasty states, which decreased their pasting properties and enthalpy, whereas the crystallization pattern was of the A + V type. Moreover, FTIR and 1 H NMR analyses suggest that the surface of WS-CA complexes is linked to CA through hydrogen bonding rather than being entirely encapsulated within its hydrophobic structure. Therefore, applying WS-CA complexes in functional food formulations presents an opportunity to develop new food products containing health benefits. • Starch V-complex aids in the preparation of low-GI starch-based foods. • Ultrasound with heat treatment achieves the functional property of A + V type starch. • Type V starch interacts with caffeic acid in the form of non-covalent bonds.