Abstract
Physicochemical properties of rice grown in Hokkaido, the northeast island of Japan, were investigated in comparison with rice grown in the other regions of Japan. Four varieties of each category were used in this experiment. The Hokkaido varieties except Norin No. 20 showed rather differences as follows from the varieties in the other regions.
(1) In the amylographic characteristics of milled rice flour, the Hokkaido varieties had somewhat higher gelatinization temperatures than the varieties in the other regions and showed clear lower values of breakdown.
(2) In the alkali digestion test of milled rice grain, the Hokkaido varieties showed pronounced disintegration.
(3) In the cooking qualities of milled rice, the Hokkaido varieties had somewhat lower values of water uptake ratio than the varieties in the other regions.
(4) In the case of cooked milled rice, the Hokkaido varieties showed lower digestibility by diastase and lower apparent elasticity than the varieties in the other regions. The cooked rice gra n of the Hokkaido varieties were also rather hard than the sample from the other regions.
Above mentioned tendency is thought to be related to lower ripening temperature of the Hokkaido varieties originated in the geographical condition.
