Abstract
Some farmers to dry the glutinous rice grains pile the unhulled rice grains dried in the sun, while they are warm and cover them with straw-mats, then dry them again in the next morning. Thereupon, this experiment was studied on the effects of the temperature upon the drying of unhulled rice grains. The results are briefly summarized as follows; 1. According to the research performed at the end of October, the temperature of the unhulled grains dried until 4∼5 P. M. was 5.5∼7.5 °C in the evening, and 6.5∼7 °C in the next morning, while that of grains piled at 1∼2 P. M. and was covered by straw-mats was 25∼29 °C in the evening and 15∼17 °C in the next morning. When they were dried again in the sun, the latter grains were dried more quickly than the former grains. 2. When the unhulled grains were kept in the thermostat regulated 23 °C during the night, the water content of the unhulled grains did not decrease remarkably, while the water content of the hulled grains (kernels) decreased, and that of the hulls increased. When the unhulled grains were kept in the normal temperature, the water content of the kernels did not decrease and the hulls were kept dry. (Generally, the water content of kernels is higher than that of hulls under normal condition.) 3. Therefore, under the high temperature, water in kernels will remove into the hulls, and this will be the reason why the high temperature of unhulled grains during the night is more favourable to be dried than the low temperature. 4. These facts above mentioned will be due to the function of hull (protective organ), therefore these facts can not be found in hulled grains (kernels).
