Effects of intrinsic crystal seed on the structure, morphology, and physicochemical properties of starch microspheres prepared by aqueous two-phase emulsion

Crystal seeds can significantly promote the growth of crystallizable polymer crystals. This study used different crystalline types of starch intrinsic crystal seeds (ICS) as homophase nucleation initiators for starch microspheres in aqueous two-phase emulsion. ICS-containing microspheres exhibited higher pasting temperatures and enthalpy than the control, and they continued pasting over a wider temperature range. XRD and SAXS analyses showed that the ICS significantly increased starch microspheres' crystallinity and structural compactness. Hence, there was a significant reduction in the particle size of the microspheres and a slight decrease in the swelling ability. Microspheres containing ICS emanated distinct polarized crosses under the polarizing microscope and showed a considerable increase in resistance to amylase hydrolysis. In addition, we found that B-type ICS promoted microsphere's ordered structure development better than the other two crystalline types. Therefore, crystal seeds can be applied as a promising strategy to modulate starch microspheres' structural and physicochemical properties.