Physicochemical and digestibility characterisation of maize starch-caffeic acid complexes

Caffeic acid and maize starches were combined to prepare maize starch-caffeic acid complexes. The physicochemical properties of the complexes were characterised by X-ray, FT-IR, RVA and DSC, while the digestibility was evaluated using an in vitro digestion model. XRD patterns revealed that the complexation with caffeic acid decreased the crystallinity of maize starch from 35.71% to 19.87%, while the crystal type remained unchanged (A-type). The solubility, swelling power and freeze-thaw stability of the complexes were greater when compared with native maize starch, and the crystal type and thermal properties were confirmed by XRD, RVA and DSC, respectively. FT-IR analysis confirmed that the short-range structure of maize starch-caffeic acid complexes was reduced since the R(1047)(/1022 )value decreased from 0.932 to 0.880. Furthermore, complexes of maize starch-caffeic acid were less amenable to in vitro digestion than native maize starch. Our study might provide an option for the utilisation of caffeic acid in food systems to reduce starch hydrolysis.