Abstract: Starch isolated from Chinese waxy rice was hydroxypropylated with propylene oxide at pH 10.5. The samples with the extent of hydroxypropylation measured as molar substitution (MS) 0.08, 0.12, 0.19 were investigated respectively. Scanning electron microscope(SEM) and X-ray diffractometry were applied to show granular size and shape, as well as their X-ray diffraction patterns. Hydroxypropylated starches show lower gelatinization parameters (To, Tp, Tc andΔH) than those of the native starch by differential scanning calorimeter (DSC). Rapid visco analyzer (RVA) showed that pasting temperature and setback values of the modified starches decrease, whereas peak viscosity increases in comparison with the native starch. The transparency and freeze- thaw stability are substantially improved.

Key words: waxy rice starch, hydroxypropylated starch, starch properties