Study on cost reduction of rice storage using polished rice

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10660240
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 農業機械学
• Research Institution: Gifu University
• Principal Investigator: GOTO Kiyokazu Gifu University Faculty of Agriculture Associate Professor, 農学部, 助教授 (60026581)
• Co-Investigator(Kenkyū-buntansha): MIWA Yoshihiro Gifu University Faculty of Agriculture Professor, 農学部, 教授 (40021703)
• Project Period (FY): 1998 – 1999
• Keywords: rice / long-term storage / cost reduction / quality / polished rice / clean rice / skin damage

Research Abstract

In Japan at present, rice is stored at low temperature with the form of brown rice. The middle/long-term rice storage using the polished rice (clean rice) was discussed from the viewpoint of cost reduction. Paddy, brown rice milled rice and two kinds of polished rice were chosen for the storage test. Also, the influence of skin damage of the brown rice on the quality change. Two stages of moisture content and storage temperature were adopted, measuring the quality index values such as grain surface color, fat acidity value, taste value of each rice form. It was confirmed that even either quality index value changes in the direction of the deterioration at the time of the storage in the high temperature, high moisture content. Especially, as for milled rice the change is big, it was most inappropriate for the form of storage. As for the polished rice, even in 25 ℃ storage the quality change is comparatively small. Also, the change width was small even for the moisture content of about 1 5%WB, if it is 15 ℃ storage. Therefore, it was judged that the storage by the form of polished rice is advantageous in respect of a cost. The storage by the paddy form is the most excellent method from the point of quality preservation, although it is hardly carried out to require big capacity and need to put to the choice from now on. Furthermore, the capacity of paddy, milled rice, polished rice were 1.62, 0.89, 0.86 respectively, when they make the capacity of brown rice 1. If brown rice storage is changed to polished rice storage, 14% of capacity decreases and the efficient application of the storage warehouse becomes possible.
Next, it became clear that skin damage exerts a big influence on the change of rice quality other than the moisture content and storage temperature in brown rice storage. Thereupon, gathering the sample with the order that the handling of conveyance etc. goes on in the facility which treats brown rice, the increase rate of skin damage degree and fat acidity value were measured. As a result, it became clear that the mechanical handling increases the skin damage and changing rate of quality becomes high. So, the plan which can make the skin damage small must be discussed at the various kinds of handling in the facility.