Understanding regulating effects of protein–anionic octenyl succinic anhydride‐modified starch interactions on the structural, rheological, digestibility and release properties of starch

Abstract Background Proteins and anionic octenyl succinic anhydride (OSA)‐modified starch (OSA‐starch) are common ingredients in food systems. The interactions between OSA‐starch and protein are found to alter the structural and functional properties of the protein–OSA‐starch complexes. In this regard, the close understanding of the relationship among the molecular interactions between whey protein isolate (WPI) and OSA–high amylose corn starch (HAS), structure changes and rheological, digestibility and release properties of WPI‐OSA‐HAS was investigated. Results The molecular interactions of WPI–OSA–HAS were significant for increasing the surface rough, solubility, storage modulus and loss modulus, but decreasing the R 1047/1022 values. For the nutritional evaluation, the anti‐digestibility of WPI–OSA–HAS was enhanced with increased resistant starch + slowly digestible starch contents and decreased equilibrium hydrolysis percentage and kinetic constant. During the digestion, part of the starch granule, OSA groups and WPI were lost, but the loss was lower than for OSA–HAS. Furthermore, the results of curcumin‐loaded WPI–OSA–HAS in simulated gastrointestinal fluids demonstrated that curcumin could be gradually released to simulate colonic fluid. Notably, the interaction between WPI and OSA–HAS depended on the WPI concentration with the stronger molecular interactions obtained at 35% concentration. Conclusion These results provided important information concerning how to adjust the rheological, anti‐digestibility and release properties of WPI–OSA–HAS through altering the electrostatic interactions and hydrophobic interactions of WPI–OSA–HAS. © 2024 Society of Chemical Industry.