• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.184-191
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• 2012

Purpose: This study was conducted to investigate the storage and quality characteristics of brown rice under the low temperature warehouse conditions using ambient cold air in the winter. Methods: This new technique maintains rough rice warehouse temperature below $15^{\circ}C$ without cooling operation until the end of May. Four hundred tons of rough rice were stored in the low temperature grain warehouse, and were aerated from the top to the bottom using ambient cold air in February. The quality of rough rice was evaluated from February through October. Results: The results were as followings. Moisture contents of rough rice in the low temperature storage had decreased less than the ordinary temperature storage. Cracked rate of brown rice in the ordinary temperature storage and low temperature storage increased by 4~10.8% and 1.6~7.2%, respectively. The germination rate of rough rice under the ordinary and the low temperature warehouse decreased by 15.0~25.0% and 1.7~8.0%, respectively. The acid value of brown rice under the ordinary and the low temperature warehouse increased by 3.67~6.72 KOH mg/100g and 3.08~4.08 KOH mg/100g, respectively. Conclusions: The result indicates that low temperature storage using ambient winter air showed better maintaining germination of rice, less change of physiological activities and cracked kernel, and better maintaining of rice quality, comparing the ordinary temperature storage.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.465-472
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• 1998

In this study short gain rough rice(Chu-cheong) with initial moisture content of around 12%(w.b.) was exposed to 3 levels of relative humidity(70, 80 and 90%) and 3 levels of temperature(20, 25 and 3$0^{\circ}C$) of the air, in order to evaluate the adsorption characteristics of rough rice and the rate of cracked kernels which will serve as the basic data when developing the quality adjusting equipment. The result showed that the moisture content of rough rice increased rapidly during the early stages of moisture adsorption like other grains, and at least 70% of the adsorption occurred within the first 24 hours of exposure to the humid environment. Adsorption rate was more related to relative humidity than the temperature of air stream, and the higher the relative humidity, the higher the adsorption rate. And the Page's equation predicted best the adsorption process of this study. Experimental results for the crack generation during the adsorption process showed that the higher the relative humidity the more the cracked kernels, and that the temperature had little effect. An empirical equation was developed to predict the crack ratio for the conditions of this study, and Nishiyama model predicted better the crack generation than Hoerl model.

• Journal of Biosystems Engineering
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• v.16 no.1
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• pp.49-59
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• 1991

A numerical model was developed to predict grain temperature, moisture content, and drymatter loss of rough rice in a grain storage bin. This model simulated conduction, natural convection, and mass transfer occuring inside a storage bin. The results obtained from the study were as follows. 1. The predicticted results agreed well with the measured results. 2. Rough rice could be store safely for one year in Suweon, Dajeon, and Jingu area. 3. Aeration of 5-day was required to control grain temperature and moisture content rise early in Jun and July, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.12-20
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• 2006

This study was carried out to investigate the relationship between each quality characteristics and changes of grain quality according to storage temperature and moisture contents of rough rice of Dongjin 1 and Siodongjinbyeo. Respiration rate of rough rice and fat acidity of brown rice were increased with moisture contents of rough rice and storage temperature. Germination rate of rough rice was the highest at $17{\sim}18%$ moisture contents of rough rice stored at low temperatures for 12 months. Germiation rate of the stored at low temperature after 16 months was up to 80% however the rate of $13{\sim}14%$ moisture contents of rough rice stored at room temperature was severely decreased to below the 10%. Gloss value of cooked rice was increased with moisture contents of rough rice and the lower storage temperature. Fat acidity of brown rice was lower in Sindongjinbyeo than Dongjin 1 at the lower storage temperature. Sensory score of cooked rice of Sindongjinbyeo which stored at low temperature for 16 months was better than Dongjin 1 and excllent at $17{\sim}18%$ moisture contents of rough rice. Correlations between sensory score of cooked rices and color b value of brown rice, gloss value of cooked rice and color L value of brown rice were significant 0.731**, 0.625*, and 0.615*, resectively, and were also positively significant correlated with break down, peak viscosity, pasting temperature, and fat acidity of brown rice -0.864**, -0.795**, -0.786**, and -0.779**, respectively.

• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.115-122
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• 1989

The objective of this study was to develop a portable auger for handling rough rice in bulk. For this purpose, a system analysis was taken for the systems of harvesting, drying, storage and transportation of rough rice and an optimal handling capacity of portable auger was determined. Then a portable auger of which capacity is 9.2 $m^3/h$ (Indica type rough rice, 19.5%, w.b.) was designed and manufactured by design requirements and tested. Test results showed that the performance of portable auger developed satisfied most design requirements.

• Journal of Biosystems Engineering
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• v.36 no.4
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• pp.267-272
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• 2011

The latent heat of vaporization in rough rice, brown rice, white rice and rice hull was calculated by Clausius-Clapeyron equation, which does not require complex constraints as in Othmer method. Equilibrium relative humidity and ratio of the latent heat of vaporization with ln$P_{\upsilon}$ and ln$P_S$ were estimated with moisture contents ranging from 10% (d.b.) to 36% (d.b.) with 2% (d.b.) increment and temperatures ranging from $10^{\circ}C$ to $50^{\circ}C$ with $2.5^{\circ}C$ increment. An empirical equation for calculating the latent heat of vaporization in rice was developed as a function of moisture content and temperature. The equation agreed well with the calculated results. The ratio for latent heat of vaporization were the greatest for white rice while they were similar among rough rice, brown rice and rice hull.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.266-270
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• 1991

Storage in the form of brown or milled rice saves space and cut cost rather than storage of rough rice, the common way of grain storage in Korea. But, brown or milled rice may be more susceptable to grain aging and sensory change than rough rice. Rice stored in government warehouse for 20 months after harvest was hulled into brown or milled rice and packaged with kraft paper bag (paper package), polyprophylen (PP package), and polyethylene (PE package). Then, after those rice packages were stored under room condition for one year, we investigated germinability, fat acidity, and sensory change to determine milling and packaging effects. Germinability of rough and brown rice was decreased significantly after long-term storge. In germination rate, Chucheong cultivar was lower than Milyang #23, brown rice was lower than rough rice, but there was no differences within packaging materials. TTC test which had a significant correlation with germinability can be used as a handy procedure for predicting grain germination. Fat acidity was increased as the order of rough < milled < brown rice in terms of milling, and PP < paper < PE package in terms of packaging materials. Especially, storage of brown rice increased fat acidity above 30 mg KOH, indicating one of characteristics of grain aging. To prevent from high fat acidity it was necessary to store in forms of rough grain with paper or PP packaging and milled rice with paper, or PP, or PE packaging. In sensory test of stored grain, eating quality in brown rice was the worst because of acidification of fatty acid. Also, eating quality of stored grain became worse as fat acidity increased.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.33-38
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• 2000

This study was performed to investigate airtight storage characteristics of rough rice using airtight flexible pve container. A storage test of rough rice of 4 tonnes was carried out to determine the changes of gas composition of air in the container, grain moisture content, air temperature and relative humidity , the presence of insects ,germination rate, crack ratio , fat acidity , 1000-kernel weight, and brown rice recovery over storage period of 5 months in Suwon. Concentration of oxygen was decreased from 20% to 16% and carbon dioxide was increased of from 0.03% to 1.6%. The grain moisture content was decreased from 14.4%(w.b) to 14.1%(w.b) for 5 months storage period . Insect population levels were low but these increased after 5 months storage. Most of insects were dead, Fat acidity increased from 7.5(mg KOH/100g) to 10.2(mg KOH/100g). Other storage factors such as germination rate, brown rice recovery and 1000-kernel , and 1000-kernel weight slightly decreased and crack ratio was slightly increased. Qualities of rough rice during 5 months storage period under hemetic air conditions were maintained fairly good considering the above changes of quality factors during storage.

• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.73-82
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• 1981

The physical properties of grain are very important for the design of handling, sorting, processing, and storage system. On the physical properties of grain, volume, bulk density, true density, specific gravity, and porosity arc the major factors affecting the thermal properties of grain. This study was conducted to determine experimentally the above physical properties of rough rice (3 Japonica-type, 3 Indica-type) and barley (covered, naked) as a function of moisture content ranged from about 10% to 25% (w.b). The results of this study are summarized as follows; 1. The volume of grain kernel increased with moisture content for both rice and barley. The volume of those grain kernel was in the range of $2.2068{\times}10^{-8}{\sim}3.3960{\times}10^{-8}m^3$ at the moisture content of 14%. 2. The bulk density of rice increased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the bulk density of barley decreased linearly with moisture content. The bulk density of the grain was in the range of 501.14~689.13kg/$m^3$ at the moisture content of 14%. 3. The true density of whole grain decreased linearly with moisture content, and was in the range of 1019.49~1139.75kg/$m^3$ at the moisture content of 14%. 4. The porosity of rice decreased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the porosity of barley increased linearly with moisture content. The porosity of the grain was in the range of 39.51~50.83% at the moisture content of 14%. 5. The regression equations of the physical properties such as volume, bulk density, true density, and porosity of the grain were determined as a function of moisture content.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1006-1010
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• 2007

This study investigated changes in the chemical and functional components of germinated rough rice for the development of functional foods. The chemical components that were determined for 'Ilpum', 'Goami2', 'Keunnun', and 'Heugkwang' rough rice cultivars included dietary fiber, free sugars, free amino acids, and functional components such as tocopherols and ${\gamma}$-oryzanol. The crude protein, fat, total dietary fiber, and free sugar contents of the rough rice increased significantly after germination. The essential amino acid content was particularly increased. After the germination of the 'Ilpum', 'Goami2', 'Keunnun', and 'Heugkwang' varieties, the following increases were found: ${\gamma}$-aminobutyric acid increased 2.4, 2.5, 6.1, and 3.4 times, respectively; ${\alpha}$-tocopherol, ${\alpha}$-tocotrienols, and ${\gamma}$-tocotrienols increased significantly; and ${\gamma}$-oryzanol content increased 0.8, 1.1, 1.5, and 1.2 times, respectively. Thus, germinated rough rice has the potential to be used as a healthy and functional food ingredient.