Effects of Ligand Concentration on the Thermal Properties, Structure, and Digestibility of Maize Starch Inclusion Complexes with Ascorbyl Palmitate

Abstract

AbstractThe alkaline method is used to form the complex between starch and ascorbyl palmitate (AP) in this study. Normal maize starch (NMS) and high amylose maize starch (HAMS) are screened to investigate the effects of AP concentrations (0%, 2.5%, 5.0%, 10.0%, 20.0%) on the properties of complexes at 60 °C. HAMS can bind more AP than NMS because of more amylose content. Comparing the endothermic peaks in DSC analysis, 5% and 10% AP levels are sufficient to interact with NMS and HAMS, respectively. The disappeared or weakened AP characteristic absorption peaks in FTIR spectra prove the formation of V‐amylose structure. The XRD analyses reveal that the inclusion complexes are formed with AP with six glucose units per turn due to the steric hindrance of AP, and the self‐aggregation of AP in the complexes is also detected. The self‐aggregation of AP do not affect the indigested ordered helical chain segments of starch in in vitro digestion. The 5% and 10% AP levels are enough to decrease the rate and extent of starch digestion in NMS and HAMS complexes, respectively. The formation of starch‐AP inclusion complexes also appear to enhance the stability of AP against light, heat, and oxidation.