Abstract
Four kinds of rice grain, i. e., Thai, Nipponbare, Koshihikari and Hiyokumochi were cooked with or without acetic acid, and the effect of acetic acid on the texture of the surface and the rice grain was examined. Rupture strength measurements showed that the hardness of only the Hiyokumochi whole cooked rice grains was increased by acetic acid, indicating that the effect of acetic acid on the hardness of the cooked rice was different from that of the non-glutinous type. An adhesion test showed that both the adhesive strain and energy of all the rice samples cooked with acetic acid were larger than those of the samples cooked without acetic acid, indicating that the stickness of any kind of cooked rice was increased by acetic acid. It was found that separately measuring both the suface and the whole of the cooked rice grain elucidated the effect of acetic acid.
