• 대한설비공학회지:설비저널
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• 제13권3호
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• pp.168-182
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• 1984

For the purpose of drying high moisture rough rice effectively, from the view point of pre-drying, some basic experiments of fluidized bed drying of rough rice were carried out. The minimum fluidization velocities $(U_{mf})$ for both rough rice and glass bead were analyzed to find out fluidizing characteristics. The main results obtained were as follows ; 1) Minimum fluidization velocity of rough rice and glass bead were 2.01m/s and 4.07m/s, respectively, when using the distributor with $16\%$ opening ratio. 2) $U_{mf}$ calculated by Shirai's empirical equation and that calculated by Wen's modified equation were inconsistent with experimental data, while $U_{mf}$ calculated by Ergun's equation was consistent with the experimental data. 3) The following equations, on the basis of Leva's equation, were obtained. $$C_{mf}=1.19\times10^{-4}(Re_p)^{-0.0318)\;(rough rice)$$ $$C_{mf}=1.02imes10^{-4}(Re_p)^{-0.0047)\;(glass bead)$$

• Journal of Biosystems Engineering
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• 제29권6호
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• pp.495-500
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• 2004

This study was performed to develop thin layer drying equations for low temperature. Thin layer drying tests of short grain rough rice were conducted at three low temperature levels of 15, 25, $35^{\circ}C$ and two relative humidity levels of 30, $50\%$, respectively. The measured moisture ratios were fitted to the selected four drying models (Page, Thompson, Simplified diffusion and Lewis model) using stepwise multiple regression analysis. The overall drying rate increased as the drying air temperature was increased and as relative humidity was decreased, but the effect of temperature increase was dominant. Half response time (Moisture ratio=0.5) of drying was affected by both drying temperature and relative humidity at drying temperature of below $25^{\circ}C$, but at $35^{\circ}C$ was mainly affected by drying temperature. The results of comparing coefficients of determination and root mean square error of moisture ratio for low drying models showed that Page model was found to fit adequately to all drying test data.

• Journal of Biosystems Engineering
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• 제5권1호
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• pp.15-23
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• 1980

Natural-air drying systems have been extensively used for cereal grains, and many researches on the systems have been conducted in foreign countries. However, little research on drying rough rice with natural air has been done. Especially . little research on natural air drying of rough rice based on weather data has been done in Korean. The objective of this study was to present fundamental data for estimating optimum requirements and basic information available for natural air drying of rough rice based on the weather data . The weather data analyzed in this study were the 10-year (1969 to 1978) record of air temperatures, wet-bulb temperatures and relative humidities, which were three-hourly observations in Taegu area. The results of this study are summarized as follows ; 1 From the results of weather data analysis the average air temperature was about $14.8^\circ$and the average relative humidty 67.5% . Average equilibrium moisture content appeared to be 13.8 percent on wet basis, which showed great potential for natural air drying in Taegue area in October. 2. Possible fan operation time based on the equilibrium moisture content of 15% on wet basis was about 14 hours a day during October in Taegu area. Probabilities of possible drying days based on minimum time available for drying in a day were analyzed. 3. Minimum air flow requirements based on the worst year were determined for different fan operation methods and initial moisture contents.

• 한국작물학회지
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• 제36권4호
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• pp.345-350
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• 1991

본 연구는 건조온도 및 방법이 미곡의 품질에 미치는 영향을 검토하는 한편 추천온도 이상으로 고온건조되어 정조의 품질이 변화된 것들을 육안감정할 수 있는 방법을 찾아내고자 시도하였다. 농산물검사소에서 수집한 추청벼, 봉광벼, 화성벼를 공시하여 초기수분함량이 약 20%인 시료를 천일건조와 건조기의 온도 43, 60, 70, 8$0^{\circ}C$에서 수분함량 약 15%까지. 8$0^{\circ}C$의 경우에는 12.5%까지 과건조하여 미곡의 품위와 관련된 쌀의 외관 및 발아율을 조사하였고, 밥의 식미검정을 실시하여 건조온도에 따른 미곡의 품질 차이를 검토하였다. 그 결과를 요약하면 다음과 같다 1. 제현율은 건조온도가 높을수록 감소하였으며, 특히 8$0^{\circ}C$ 이상에서 현저히 감소하였고, 정백율은 화성벼가 추청과 봉광에 비해 낮은 경향이었으며 건조온도별로 유의한 차이는 있었으나 그 값은 8$0^{\circ}C$ 건조조건에서도 차이가 적었다 2 동할미 및 쇄미의 비율은 추청, 화성, 봉광벼 순으로 적었고, 피할립, 사미 및 착색미 비율이 10%미만(농산물검사기준의 현미 1등품기준) 인 건조조건은 천 일 건조와 43$^{\circ}C$건조였으며, 20%미만 (2등품기준)인 경우는 천일건조, 43$^{\circ}C$건조. 6$0^{\circ}C$건조에서였다. 한편 백미의 쇄미율이 정부관리쌀 기준인 5%이하에 적합한 건조조건은 천일건조와, 43$^{\circ}C$건조였다. 3. 발아율은 정상발아검정과 저온검정 모두에서 봉광. 추청, 화성벼 순으로 높았으며, 43$^{\circ}C$ 건조조건과 천일건조와는 큰 차이는 없었으나 이보다 높은 건조온도조건에서의 발아율은 현저히 감소하였다. 4. 현미의 백도는 추청, 봉광, 화성벼 순으로 높았으며 건조온도가 높을수록 증가하였다. 백미의 경우에는 봉광벼가 추청벼와 화성벼보다 높았으며, 8$0^{\circ}C$ 건조조건에서 유의하게 낮았다. 5 밥의 종합식미는 세품종 모두 기준인 천일건조 쌀보다 화력건조한 쌀의 평가치가 낮았으며 건조온도가 높을수록 낮았다. 6. 미곡의 품질은 현행 수분함량 측정과 기행하여 육안감정으로 동할미 및 쇄미 비율을 평가하는 것이 타당할 것으로 판단되었다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.877-885
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• 1993

Three types of solar grain dryers, namely , the solar grain bin dryer, the solar greenhouse rotary drum dryer and small scale solar green house tray dryer, have been tested. The results showed that each type of solar grain dryer has its feature. These solar drying units have three main advantages : (1) Required commercial energy to remove 1Kg moist from rough rice is only 5.3% to 15.8% of the energy consumed by common heated dryer : 2) The area of solar drying system is only about 10% of the area of the sunny ground to give equal drying capacity ; (3) There are good drying quality in the moisture uniform , germination percentage, and grain color.

• 한국식품과학회지
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• 제38권4호
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• pp.506-512
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• 2006

전해수로 처리한 생식 원료 백미, 현미, 찹쌀, 보리를 열풍건조 및 동결건조를 실시하여 이화학적 특성 및 기능성 성분의 변화를 조사하였다. 백미, 현미, 찹쌀, 보리의 단백질, 지방, 탄수화물, 회분 등 성분의 함량은 전해수로 처리하여 열풍건조 및 동결건조를 통하여서는 거의 변화가 없는 것으로 나타났다. 백미, 현미, 찹쌀, 보리는 전해수로 처리하여 열풍건조 및 동결건조를 실시한 후 L값과 a값이 변화가 없는 것으로 관찰되었고 백미와 찹쌀의 열풍건조를 실시한 시료가 증가한 것으로 나타났으나 전해수로 처리하고 동결건조를 실시한 시료와 전해수 처리를 하지 않고 동결건조를 실시한 시료는 차이가 없는 것으로 나타났다. 식이섬유의 함량은 열풍친조를 실시한 시료가 증가를 나타냈으나 전해수로 처리한 시료와 처리하지 많은 시료 사이에는 차이가 없는 것으로 나타났다. 백미, 현미, 찹쌀, 보리 중의 niacin 함량과 보리 중의 ${\beta}-glucan$ 함량은 열풍건조 및 동결건조를 실시한 시료가 서로 차이를 보이지만 전해수로 처리하여 동결건조를 실시한 시료와 전해수로 처리하지 않고 동결건조를 실시한 시료 사이에는 차이가 없는 것으로 나타났다. 동결건조를 진행한 시료는 전해수 처리 전후 이화학적 특성과 기능성 성분 함량이 변화가 없는 것으로 나타났다. 결론적으로, 생식 원료 중 곡류인 백미, 현미, 찹쌀, 보리의 전해수 처리 시 이들의 이화학적 특성 중 단백질, 지방, 및 탄수화물, 회분, 및 식이섬유의 함량과 색도에는 영향을 주지 않았고 기능성 물질 중 niacin과 ${\beta}-glucan$의 함량은 전해수 처리 후 열풍건조 시 약간의 영향을 나타냈으나 동결건조 시에는 전혀 영향을 주지 않았으므로 전해수를 이용한 세척을 생식 제조에 충분히 사용이 가능하다고 생각된다.

• Journal of Biosystems Engineering
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• 제31권4호
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• pp.349-354
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• 2006

This study was performed to evaluate the performances for a concurrent flow rice dryer of pilot scale with devices for circulating rice. The pilot scale dryer with the capacity of 700 kg was developed to obtain design informations for the development of actual scale dryer of holding capacity of 10 tons. Three drying tests were conducted at two temperature levels of $100^{\circ}C\;and\;120^{\circ}C$, and two air flow rates levels of $28.5cmm/m^2\;and\;57.1cmm/m^2$. Drying conditions for Test-1, Test-2 and Test-3 were $100^{\circ}C\;-28.5cmm/m^2,\;120^{\circ}C-28.5cmm/m^2\;and\;120^{\circ}-57.1cmm/m^2}$ respectively. Drying rates were 0.73%(w.b./h) for Test-1, 0.90%(w.b./h) for Test-2 and 1.46%(w.b./h) for Test-3. The crack ratios of brown rice after drying ranged from 2.4% to 8.4%, and increased with the increase of drying rate and airflow rate. The energy consumptions were from 6,225 kJ/kg to 6,993 kJ/kg which was higher than that of conventional cross-flow rice circulating type dryer used in Korea. This results were due to the lower ambient air temperatures of $4.5^{\circ}C\;to\;13.4^{\circ}C$ during drying tests.

• 한국초지조사료학회지
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• 제33권4호
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• pp.234-239
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• 2013

This study investigated the effects of drying methods and drying time on the changes in anthocyanin content in colored barley. Colored barley cultivar Boanchalbori was harvested at a time when the anthocyanin content was the most and dried in afield. The harvested barley was then treated by two methods, sun drying and shade drying, for 4, 8, 24, and 32 h. The moisture content of the sun-dried barley decreased slightly faster than shade-dried samples, but the difference was not statistically significant. Chemical analysis indicated that the samples dried under shaded conditions had slightly higher crude fiber and lower nitrogen free extract, but the difference was not statistically significant. There was no difference in the total digestible nutrients between the two methods. In the case of sun-dried barley, the anthocyanin content decreased compared to the control and shade-dried samples after drying for 4 h (p < 0.05), was maintained at a constant level at 24 h, and then decreased at 32 h. In case of shade-dried barley, the anthocyanin content decreased gradually with the drying time, and a significant decrease was found at 24 h of drying (p<0.05) as compared to the control. The shade-dried method was more successful in reducing anthocyanin loss than the sun-dried method (p<0.05). There was a slight decrease in 1,1-Diphenyl-2-Picrylhydrazyl radical scavenging with drying time in the shade-dried method, and a significant decrease after 4 h with the sun-dried method. These results showed that covering with a two-layer awning was advantageous to dry colored barley in the field conditions.

• 한국식품과학회지
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• 제31권3호
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• pp.625-630
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• 1999

효소식품인 현미코오지를 제조한 후 마이크로파 진공건조를 적용하여 건조하고 그 건조특성과 효소활성을 열풍건조, 진공건조, 또는 동결건조의 경우와 비교해 보았다. 마이크로파 진공건조의 경우 열전달속도가 빨라 건조 시작후 $5{\sim}10$분만에 $40^{\circ}C$에 도달한 후 건조시간 내내 $40{\pm}2^{\circ}C$를 유지하였다. 열풍건조의 경우는 건조시작 10분 경과 후, 진공건조의 경우는 40분 경과 후 $40^{\circ}C$에 도달하였다. 마이크로파 진공건조의 경우 건조 2시간 후 수분함량 0.08 kg water/kg solid까지 감소하였으나, 열풍건조의 경우 건조 시작후 2시간이 경과했는데도 겨우 수분함량 0.70 kg water/kg solid까지만 감소하였다. 마이크로파 진공건조의 경우는 초기 건조속도는 0.06 kg water/kg solid/min이었으며 처음부터 건조속도가 계속 감소하는 감률건조를 보였다. 열풍건조의 경우는 건조 초기 건조속도가 0.0045kg water/kg solid/min으로서 마이크로파 진공건조의 1/10 이하였으며 건조개시 40분까지 항률건조를 보이다가 임계수분함량 0.89 kg water/kg solid 부근부터 감률건조가 시작되었다. 건조시료의 ${\alpha}-amylase$ 활력, diastatic activity 및 protease 활력은 마이크로파 진공건조, 동결건조, 진공건조 및 열풍건조의 순서를 보여 마이크로파 진공건조의 품질보존효과를 알 수 있었다.

• Journal of Biosystems Engineering
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• 제25권3호
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• pp.227-232
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• 2000

A natural air in-bin grain dryer with a grain circulator was developed for on farm use. Natural air drying test for rough rice was carried out to evaluate drying rate, uniformity of moisture content distribution in grain bed and energy consumption. It took 10 days to dry 8 ton of paddy rice from 21.9%(w.b) of moisture contents to 16.7%(w.b), by prototype dryer and the average drying rate was 0.52%/day. The uniformity of moisture content after drying was superior to a conventional natural air dryer in which grains were not mixed during drying periods. The dryer performance evaluation index was 738.3kJ/(kg.water), which was more effective than that of grain circulation type hot air dryer(3,500∼5,000 kJ/kg.water)