1996 Fiscal Year Final Research Report Summary
Studies on fissure caused by moisture adsorptio in rough rice
| Project/Area Number |
07660334
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
農業機械学
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| Research Institution | Hirosaki University |
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Principal Investigator |
BEKKI Eiji Hirosaki University, Faculty of Agriculture, Professor, 農学部, 教授 (30003429)
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| Project Period (FY) |
1995 – 1996
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| Keywords | fissure / adsorption / rough rice / brown rice / rate of adsorption / adsorption isotherm / water vapor pressure / adsorption potential |
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| Research Abstract |
Experiments in 1995 utilized a microscopic CCD camera set inside an air oven with temperature and humidity controls purchased under the grant-in-aid program for scientific research. The fissuring behavior of a brown rice kernel in an adsorptive environment was recorded in a video-casette tape using the said camera. The video tape was replayd and on a TV screen the exact time when fissure started and developed was determined. Air conditions in the oven were varied at 80,85,90 and 95% humidity and temperatures of 10,20, and 30ﾟC.The occurrence of fissure were : none in grain with 17.3% moisture, few in grain with 15.3% moisture at 30ﾟC-95% RH,great in overdried grain (12.7% moisture), and greatest in excessively dried grain (10.7% moisture) at all temperature levels and above 85% RH.Majority of overdried grains suddenly fissured in the central part and rapidly extend to the outer part after 1 to 2 hours from the start of drying.
The cause of fissure were done using the same oven in the 1996 experiments. In desorption, fissure occurred from 40ﾟC and above. In adsorption when grains were exposed to near saturated air, fissure did not occur in grains with 20.2% moisture, while the rate of occurrence increased with a decrease in initial moisture content, and heavy occurrence in overdried grains (12.7% moisture) at all temperature levels. Adsorption isotherms for 10,20,30 and 40ﾟC were drawn from which grain equilibrium moisture content were given at 40 to 95% RH.The results discussed the relationship of fissuring to : grain expansion and contraction, rate of desorption and adsorption, and adsorption potential. Rice expansion-contraction and lateral-longitudinal ratios were unique among elastic bodies. Adsorption and desorption were caused by the difference in water vapor pressure. The driving force is the adsorption potential which depends on humidity.
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