Abstract
We determined the degree of gelatinization of rice grains by the β-amylase-pullulanase method to examine the effects of various treatments on the gelatinization of rice grains. Hot water-treated rice (abnormally cooked rice), which was kept at 75°C for 8h or at 75°C for 18h, showed a high degree of gelatinization, similar to that of rice cooked automatically in an electric cooker. However, the degree of gelatinization of abnormally cooked rice kept at 75°C for 4h was low, like that of aged rice prepared from automatically cooked rice by storage at 5°C for 96h. On the other hand, the degree of gelatinization of warm water-treated rice kept at 50°C for 72h or at 60°C for 72h, was lower than that of raw rice. The degree of gelatinization determined by the β-amylase-pullulanase method was in agreement with the results obtained by X-ray diffraction and the water uptake behavior of the rice grains.
