The rice grains ( Oryaa sativa L. Japonica, cultivar Koshihikari) harvested in Niigata prefecture in 1994 was soaked in water, and subjected to high pressure treatment at 400MPa for 10min. The rice thus high-pressure-treated was then boiled for cooking. The physical properties of the cooked rice were compared with those of a control rice with respect to the hardness, stickiness and conductivity immediately after cooking, and also with respect to those with time during the storage. The highpressure-treated rice exhibited higher stickiness than the control rice immediately after cooking, but it became harder than the control rice the next day. Furthermore, the high-pressure-treated rice exhibited higher conductivity immediately after cooking than the control rice, and the conductivity increased with time during the storage. Scanning electron micrographs (SEM) indicated that the grains of the highpressure-treated rice were swollen by the high pressure treatment, with water effectively penetrating into the peripheral portion of each starch granule, and when such rice was cooked, deep vacant holes and thick walls of starch gel were formed in each grain. It has been confirmed that the rice subjected to such high pressure treatment, when cooked, is tasty even after becoming hard with time during storage.
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