Grain Quality and Eating Quality of Rice Grown in Hokkaido and in Other Prefectures of Japan

Abstract

We investigated grain quality and eating quality of 56 rice samples of 3 crop years and of 12 varieties grown in Hokkaido and in other prefectures of Japan by assessment of physicochemical properties and sensory evaluation. Protein contents, amylose contents and pasting properties of Hokkaido-grown rice were improved and almost the same as those of rice grown in other prefectures. There were no differences in Mido value, appearance, hardness and stickiness of cooked rice between Hokkaido-grown rice and rice grown in other prefectures. Eating quality of Hokkaido-grown rice was slightly better than that of rice grown in other prefectures. Passage of time after cooking resulted in deterioration of eating quality, but the degree of deterioration in eating quality of Hokkaido-grown rice was similar to or even less than that of rice grown in other prefectures. There was no significant correlation between protein content and eating quality or between amylose content and eating quality. Accordingly, the protein contents and the amylose contents of rice are mostly in the appropriate range in terms of eating quality. The results of this study indicated that the grain quality and eating quality of Hokkaido-grown rice have been improved to levels similar to or even better than those of rice grown in other prefectures. The improvement in grain quality and eating quality of Hokkaido-grown rice is thought to be due to breeding of new rice varieties and the development of cultivation control techniques and post-harvest techniques.