Preparation and characterization of a new type of porous starch microspheres (PSM) and effect of physicochemical properties on water uptake rate.

Porous starch (PS) is a multifunctional biomaterial and has been widely applied in both pharmaceutical and food industry. This study was carried out to develop a new type of porous starch microspheres (PSM) through the dual-modification of the alcohol-alkaline treatment and inverse crosslinking-emulsion method, which could rapidly uptake water. The chemical and physical characteristics of the PSMs were determined by FTIR, SEM, XRD, DSC, ESD (equilibrium swelling ratio) and WS (water solubility). The results showed that PSMs could reach its saturated water uptake volume (about 1 mL/100 mg) in 60 s. The PSMs also revealed rough surface with observable pores and lower crystallinity degree after the dual-modification according to SEM and XRD. The use of epichlorohydrin (ECH) as a crosslinking agent could introduce crosslinks between starch molecular chains, which was determined by ESD, WS and the thermal properties. These results indicated that the dual-modification could be successfully used for preparation of rapid water uptake PSMs with enhanced structure stability.