92D-9 |
Evaluation of short-grain rice quality based on some physicochemical criteria under selected storage conditions |
J. I. JUNG1, H. Kim2, S. U. Lee1, D. C. Kim1, and B. K. Kim3. (1) Div. of Food Marketing Technology, Korea Food Research Institute, Seungnam, 463-420, South Korea, (2) Food Protein R&D Ctr., Texas A&M Univ., Cater-Mattil Hall, 2476 TAMU, College Station, TX 77843-2476, (3) Dept. of Food Engineering, Dan Kook Univ., San-29, Anseo-Dong, Cheonan, 330-714, South Korea Rice is subjected to various postharvest handlings depending on the regional conditions. As the surplus rice accumulates in Korea, extended storage of rice without seriously affecting the quality is required. Understanding the interactive effects of postharvest conditions (kernel MC and temp) currently practiced in this area will help for safer storage of rice. To predict the safe storage period of polished rice by evaluating the physicochemical quality attributes of rice kernel as interactively affected by some storage conditions. Short-grain rice cultivar Ilpoom, was harvested in Korea with a rough rice moisture content(MC) of 20.1%. After immediate milling, the polished rice was air-dried to the equilibrated MC of 14, 16, and 18.0%. Rice packed in a laminated polyethylene-film bag (2-kg size) was subsequently stored at 5, 15, and 25C for 16 weeks. The physicochemical quality attributes of rice have been analyzed weekly. At day 14, grain had started to lose weight until total loss of weight reached to about 0.02-1.42% during 112 days of storage. Acidity value, as an indicative of fat deterioration required wide ranges of days, namely, 84(18%)-105(14%) days at 5C , 44-77 days at 15C, and 7-35 days at 25C , respectively. No significant changes in colorimetric values were noted, however, under extreme MC(18%) and temp(25C), the whiteness value has fallen down to 38 at day 14 and was proven unacceptable. The amylographic peak viscosity was almost unaffected while consistency values were negatively (at low MC) or positively (at longer storage) affected. The SEM micrographs revealed the appearance of white powderly spots on the roughened surface at 30 (18% MC) and 60 (16% MC) days of storage at 25C. The kernel MC of 15.5-16.5% and storage temp at below 15C was highly recommended to maintain the quality of short-grain polished rice (Ilpoom variety) within acceptable ranges during the storage period.
Session 92D, Quality Assurance: General
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