Effects of crosslinking temperature and time on microstructure and stability of cassava starch microspheres.

Starch microspheres (SMs) were prepared by a water-in-water emulsion-crosslinking technique at 4 °C and 30 °C for 1, 6, 12 and 24h; the SMs obtained were analyzed for crosslinking density, morphology, crystalline structure, and stability against temperature, pH, and α-amylase hydrolysis. The crosslinking degree at 30 °C was considerably higher than that at 4 °C. SMs prepared at 4 °C for less than 12h incubation had larger size and more porous structure as compared with those prepared at 30 °C, but the morphology became comparable (spherical shape with smooth surface and dense structure) after 24h incubation. All SMs samples displayed amorphous structure. Stability tests revealed that the SMs were very stable under acidic and mild basic pH; however, stability against α-amylase hydrolysis varied depending on incubation temperature and time.