Changes in Nonwaxy J aponica Rice Grain Textural‐Related Properties during Cooking

Changes in physicochemical rice grain properties during cooking were examined using five nonwaxy, Japonica cultivars. The grain moisture increased as temperature increased during heating, although there were slight differences among some cultivars from 30C to 70C. A marked decrease in overall firmness was found between 85C and cooked. Awayukikomachi, low‐amylose content rice, showed lower firmness than the other cultivars during cooking. The leached materials in grain–water mixture increased between 50C and 70C. These results indicated that rice grain attributes affected not only cooked grain quality, but also changes in textural‐related grain properties during cooking. Pearson's product‐moment correlation coefficients between grain moisture at 50C versus overall firmness and surface firmness during cooking showed high, negative correlations (r = −0.88 and r = −0.71) with significant differences. This result indicated that grain moisture at 50C played a role in the textural property of cooked rice grains. Practical Applications Generally, the raw rice quality is directly related with cooked rice quality; cooking procedure and/or condition also affect cooked rice quality. Although the cooking procedure was fixed in this study, changes in physicochemical rice grain properties during cooking and relationships among grain attributes were examined to elucidate which procedure, condition or attributes would be mainly influenced in the cooked rice quality. Our results could contribute to develop newly rice cooking method or apparatus.