Substituent distribution changes the pasting and emulsion properties of octenylsuccinate starch

• Octenylsuccinate (OS) starch was prepared under high shear conditions.
• OS groups were located near the branching points and non-reducing ends of amylopectin.
• OS groups exposed outside of non-reducing ends would give more stabilized emulsion.

An improved preparation method of octenylsuccinate (OS) starch under high shear condition was described in this study. The distribution of OS substituents at the granular and molecular levels was assessed by confocal laser scanning microscopy (CLSM), β-amylase hydrolysis, chromatographic and 1H NMR techniques. We found that the OS group distribution could change the pasting and emulsion properties of OS starches. Specifically, more uniform OS group distribution was identified in the central region of OS starch granules prepared under high shear condition (H–OS–starch), and OS groups were located both near the branching points and the non-reducing ends. More OS groups exposed outside of non-reducing ends would access the interface between oil and water and give more stabilized emulsion.