Effect of Endogenous Hydrolytic Enzymes on Glucose Liberation and Ecotypical Difference in Hot-water-treated Rice Grains (Oryza sativa L.)

抄録

We observed clear differences in glucose accumulation in milled grains between 8 japonica and 8 indica rice (Oryza sativa L.) cultivars subjected to hot-water (60°C) treatment for 30 min. The mean glucose content increased rapidly, from 8.9 to 123 mg/100 g DW in japonica grains and 4.6 to 54 mg/100 g DW in indica grains. The difference in glucose content between the two ecotypes corresponded to the observed significant difference in hydrolytic activities on gelatinized starch, which were much higher in japonica grains. Whereas, the mean α-glucosidase activity of the two ecotypes did not significantly differ. There was a significant correlation between the glucose content under hot-water treatment and glucose liberating enzyme activity.