By examining Japonica rice and Indica rice, we obtained the following results:
(1) General evaluation in the sensory test showed that Akitakomachi was most favored. Indica rice was dull, hard and not very sticky. Its taste was not well liked. RINX-89 was sticky, soft and had a unique fragrance.
(2) Iodine absorption of the solution extracted during cooking Indica rice was higher than that of Japonica rice. Indica rice contained much more protein than Japonica rice.
(3) Amylogram characteristics had a significant correlation with viscosity. Indica rice had higher gelatinization temperature, while Japonica rice and RINX-89 had higher maximum viscosity, break-down and final viscosity.
(4) The water in which cooked Japonica rice was rinsed contained higher total amounts of sugar and reducing sugar than Indica rice. This showed a correlation with taste evalution. Indica rice had a higher β-amylolysis limit. This was assumed to be caused by the difference between starch on the surface of cooked Jndica rice and that of cooked Japonica rice.
(5) Sugar composition of the water in which cooked rice had been rinsed differed from rice to rice: Koshihikari and Akitakomachi contained more G1, G2, G3, while Hoshiyutaka and A 1-333 had less G1, G2, G3.
(6) The sensory test of rice cooked by different methods showed that Indica rice was more suitable for being cooked as butter-rice than by ordinary rice-cooker method.
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