Storage Life and Taste of Rice Unusually Long Term Stored at a Low Temperature

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07660350
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 生物環境
• Research Institution: Nihon University
• Principal Investigator: MORISHIMA Hiroshi Nihon University, College of Bioresource Sciences, Professor, 生物資源科学部, 教授 (90011832)
• Co-Investigator(Kenkyū-buntansha): SAKAI Naoki University of Tsukuba, Division of Agriculture and Forestry, Professor, 農林学系, 教授 (00092213) ; TODA Setsuo Nihon University, College of Bioresource Sciences, Lecturer, 生物資源科学部, 講師 (50060041)
• Project Period (FY): 1995 – 1996
• Keywords: vey long term cold storage of paddy / quality of rice / germination percentage / activity of embryo / fatty acid / taste of long term stored rice / total count of living bacteria / percentage of so calles Red Ps.

Research Abstract

Quality changes of very long term cold stored paddy were examined. From 1976 till 1994, rice, cultivar NIPPON-BARE,had been cultured and harvested every year at the same paddy field of the Experimental Farm of the University of Tokyo, under a fixed cropping pattern including planting distance and fertilizer application. Paddy was combine harvested after sufficient ripening and sun drying. Paddy had been stored every year in a cold storage at the temperature of 3-5ﾟC.Qualities of rice, including whiteness of both brown and milled rice, moisture content, germination percentage, fatty acid, amylose percentage, taste index measured by SATAKE-TASTE ANALYZER by means of NIR method, percentage of fungi infected grain and microflola, were examined. Chronologically speaking, germination percentage had kept almost constant for 7 years about 80% or more, however, it decreased rapidly immediately after that period. After ten years storage, the germination percentage fell to zero. Although fatty acid had maintained relatively low value by the effect of cold storage, it increased gradually according to storage term lengthend. Whiteness of brown rice decreased as stored year increased, but that of milled rice did not show apparent trend. Moisture content increased by the influence of low temperature and relatively humid atmosphere in the storage. Taste of rice had significantly got worse as the storage year increased. Fungi infected percentage did not give significant influence on other evaluation factors. Total count of living bacteria was in the order of 10 ^7count/grain at first, and decreased as the storage time passed. Percentage of so-called Red Pseudomonas appointed by IIZUKA and ITOH,to the total living bacteria increased as the storage time passed.