Abstract
The relationship between the activities of endogenous enzymes in milled rice and the accumulation of chemical components in the rice grains during cooking was compared for four milling yields of Koshihikari. Sugars, particularly glucose, in the rice grains accumulated during cooking for all milling yields, especially for the higher yields. Reducing sugars and amino acids accumulated more for lower milling yields than for the higher yields. A comparison the thermal dependence of the hydrolytic activities showed that the glucosidase activity at 60°C was characteristically high in 85% and 90% milled rice, although the amylase activity at 30°C and proteolytic activity at 40-60°C was relatively high in 95% and 100% milled rice. The gelatinization properties were similar for all milling yields. Although glucose accumulation in rice grains at 60°C is characteristic during cooking for all milling yields, the difference in behavior of endogenous enzymes between different milling yields may affect the accumulation of chemical components during rice cooking.
