Abstract
For Japanese agriculture, various methods of cost reduction in rice production are investigated. On the other hand, consumers require the high quality and tasty rice. We then considered the optimum condition for rice storage in grain silo of country elevator from the viewpoints of energy saving and quality preservation. The paddy storage test of various combinations of moisture content and storage temperature was carried out, and the change of fat acidity value, which is usually used as an index of rice quality, was analyzed introducing the integrated temperature. The following results were obtained.
1) While the storage term is less than one year, the fat acidity value increases linearly with time elapsed. The higher the moisture content is, and the higher the storage temperature is, the faster the increasing rate is. We then described the change of fat acidity value using the integrated temperature during the storage.
2) The optimum standard values for the calculation of integrated temperature were around 10°C for the every levels of paddy moisture content ranging from 12 to 17% (WB). So the standard temperature of integrated temperature was determined as 10°C for the ease of calculation.
3) The equation to estimate the fat acidity value was set up using the integrated temperature and the fat acidity value increasing rate (A) which describes the effect of paddy moisture content.
4) Since the standard temperature is 10°C, the storage temperature of lower than 10°C is useless from the aspect of fat acidity value.
5) The optimum storage temperature can be obtained using the estimating equation according to the paddy moisture content and the tolerance limit of fat acidity value.
