Abstract
The ratio of the cracked rice which were immersed in water for a limited time was measured under the various conditions of the rice grain and the temperature of water in order to reveal the cracking mechanism of polished rice during soaking.
The measurement showed that the cracking closely related with moisture content and water temperature.
From the observation of the cracked grains a particular direction was observed for the developed line of cracks. Therefore the polished rice grains were cut into ventral portions and dorsal portions, and the coefficients of thermal and hygroscopic expansion, and the difference of partial water penetration were measured.
The analyzed data showed that the formation of the cracks depended on the partial difference of water penetration into the grains.
