• Asian-Australasian Journal of Animal Sciences
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• 제27권11호
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• pp.1615-1622
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• 2014

An accurate assessment of moisture content in feed ingredients is important because moisture influences the nutritional evaluation of feedstuffs. The objective of this study was to evaluate various methods for moisture content determination. In Exp. 1, the weight loss on drying (LOD) of corn, soybean meal (SBM), distillers dried grains with solubles (DDGS), whey permeate, whey powder, spray-dried porcine plasma (SDPP), fish meal, and a mixed diet of these 7 ingredients were measured by oven drying at $135^{\circ}C$ for 2 h. Additionally, the samples were dried at $105^{\circ}C$ for 3, 6, 9, 12, or 15 h. The LOD contents of the DDGS, whey permeate, and whey powder measured by drying at $135^{\circ}C$ for 2 h were greater than the values measured by drying at $105^{\circ}C$ for 3 h (p<0.05). All samples except SDPP (p = 0.70) dried at $105^{\circ}C$ for 6, 9, 12, or 15 h caused more LOD compared with the samples dried for at $105^{\circ}C$ for 3 h (p<0.05). The LOD contents of the individual ingredients were additive when dried at $105^{\circ}C$ regardless of drying time. In Exp. 2, moisture contents of corn, SBM, wheat, whey permeate, whey powder, lactose, and 2 sources of DDGS (DDGS1 and DDGS2) were measured by the Karl Fischer method, oven drying at $135^{\circ}C$ for 2 h, and oven drying at $125^{\circ}C$, $115^{\circ}C$, $105^{\circ}C$, or $95^{\circ}C$ for increasing drying time from 1 to 24 h. Drying samples at $135^{\circ}C$ for 2 h resulted in higher moisture content in whey permeate (7.5% vs 3.0%), whey powder (7.7% vs 3.8%), DDGS1 (11.4% vs 7.5%), and DDGS2 (13.1% vs 8.8%) compared with the Karl Fischer method (p<0.05). Whey permeate and whey powder were considerably darkened as the drying time increased. In conclusion, drying samples at $135^{\circ}C$ for 2 h is not appropriate for determining the moisture content in whey permeate, whey powder, or DDGS as well as the mixed diet containing these ingredients. The oven-drying method at $105^{\circ}C$ for 5 to 6 h appears to be appropriate for whey permeate and whey powder, and at $105^{\circ}C$ for 2 to 3 h for DDGS.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.101-110
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• 2014

Purpose: The purpose of this study is to develop a system to optimize drying potential energy of the exhausted hot air by changing relative humidity of the air. This study modified the conventional drying method into a drying method changing exhaust cycle and time in order to control the relative humidity of the exhausted hot air during drying process. Method: A valve on the vent was controlled according to a preset time to change the exhaust cycle and time. This study analyzed the influence of the two different types of drying method on the drying characteristics, required energy, and quality of the dried peppers: conventional drying method exhausting hot air continuously and new drying method controlling exhaust cycle and time. Results: Drying characteristics based on exhaust time showed that drying time increased with exhaust time, and specific energy consumption was reduced by 28% from 18.39 MJ/kg (conventional method) to 13.24 MJ/kg when exhaust time was set to one minute. Drying characteristics based on heating time showed that drying time increased with heating time and specific energy consumption was reduced by 30% from 18.39 MJ/kg (conventional method) to 12.87 MJ/kg when exhaust time was set to 22 minutes. Drying characteristics based on exhaust cycle showed that drying time increased with exhaust cycle, and specific energy consumption was reduced by 31% from 18.39 MJ/kg (conventional method) to 12.69 MJ/kg when exhaust time was set to one minute and exhaust cycle was set to 22 minutes before drying and 40 minutes after drying. The quality of the dried red peppers showed that capsaicin, color, and sugar content were high as 34.87 mg/100g, 66.33, and 11.87%, respectively, when exhaust time was set to one minute and exhaust cycle was set to 22 minutes before drying and 40 minutes after drying. Conclusions: In order to utilize the drying potential energy of the exhausted air during drying process, the conventional drying method was modified into the drying method controlling exhaust cycle and time. The results showed that drying with exhaust cycle of one minute was more efficient in terms of drying time, required energy, and quality of the dried peppers than the one with exhaust cycle of 20~40 minutes.

• Journal of Biosystems Engineering
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• 제1권1호
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• pp.55-55
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• 1976

An experimental work was conducted to develop an optimum operating system of various hay drying systems ; sun-drying with long hay, sun-drying after chopping, sun-drying after crushing, heated air drying after chopping using batch-type dryer and heated air drying after crushing using tunnel-type dryer. Seombody having 60 cm long and initial moisture content of approximately 79 % in wet basis was used for the experiment. The criteria selected for determining the optimum operating condition were the drying performance rate, the production cost and quality of dried matter of each drying systems. The result of this study are summarized as follows : 1. Drying characteristics of leaves of long stem hay, chopped seombody and crushed one were obtained by maintaining the oven temperature at 70 degrees centigrade. The required drying times for various samples to approximately 15% moisture content in wet basis were about 50 min .for leaves ; 160 min. for crushed hay ; 250 min. for chopped hay ; 340min. for ling hay and more than 360 min .for stems. The drying time of crushed hay was required about 50 % of that for the uncrushed long hay. Such a significant difference of drying of time between the leaf and long stem may indicate that an effective drying of seombody may not be achieved unless any kind of special process treatment for the whole hay is undertaken. 2. In each individual drying system, the following conclusions were drawn: a. After 8 days sun-drying on concrete floor under good days with average tempe?rature at $256{\circ}C$ and relative humidity at 55% at 2 P.M., the moisture content of long hay was still above 25 5'~ and the leaf loss during drying caused by wind and rough handling was more than 50 ~G. b. It was possible to dry the chopped seombody by sun-drying down to about 10 % moisture content within 5 days, however, a stock of heat and discolouration phenomena were observed during the drying, which may be due to the increased deposit-density by chopping, resulting in lowering the quality of the dried product. c. Sun-drying for the crushed material by hay-conditioner was required about 4 days to reduce the moisture content to about 10 %, keeping the quality of dried product at good grade. o. The optimum deposit-depth of the chopped seombody in the batch-type dryer used was about 28cm with about 42kg/hr of drying performance rate. However, it was necessary to overturn the materials between the upper and lower layers in order to obtain a good quality of dried product. d. The drying performance rate by the tunnel-type drier was highest among those of drying systems tested, giving the rate of approximately 400kg/day. 3. On reviewing the individual drying system for seombody, it was possible to draw conclusion that the best system was tunnel drying with the crushed seombody as far as the performance rate was concerned. However, the methods gives the highest operational cost. The system for the lowest operational cost with good quality of dried product was the sun-drying with the crushed material. Accordingly, it may be recommended that the system of sun-drying for the crushed seombody may be the most feasible system presently applicable to farm-level operation.

• Journal of Biosystems Engineering
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• 제1권1호
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• pp.56-63
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• 1976

An experimental work was conducted to develop an optimum operating system of various hay drying systems ; sun-drying with long hay, sun-drying after chopping, sun-drying after crushing, heated air drying after chopping using batch-type dryer and heated air drying after crushing using tunnel-type dryer. Seombody having 60 cm long and initial moisture content of approximately 79 % in wet basis was used for the experiment. The criteria selected for determining the optimum operating condition were the drying performance rate, the production cost and quality of dried matter of each drying systems. The result of this study are summarized as follows : 1. Drying characteristics of leaves of long stem hay, chopped seombody and crushed one were obtained by maintaining the oven temperature at 70 degrees centigrade. The required drying times for various samples to approximately 15% moisture content in wet basis were about 50 min .for leaves ; 160 min. for crushed hay ; 250 min. for chopped hay ; 340min. for ling hay and more than 360 min .for stems. The drying time of crushed hay was required about 50 % of that for the uncrushed long hay. Such a significant difference of drying of time between the leaf and long stem may indicate that an effective drying of seombody may not be achieved unless any kind of special process treatment for the whole hay is undertaken. 2. In each individual drying system, the following conclusions were drawn: a. After 8 days sun-drying on concrete floor under good days with average tempe\ulcornerrature at $256{\circ}C$ and relative humidity at 55% at 2 P.M., the moisture content of long hay was still above 25 5'~ and the leaf loss during drying caused by wind and rough handling was more than 50 ~G. b. It was possible to dry the chopped seombody by sun-drying down to about 10 % moisture content within 5 days, however, a stock of heat and discolouration phenomena were observed during the drying, which may be due to the increased deposit-density by chopping, resulting in lowering the quality of the dried product. c. Sun-drying for the crushed material by hay-conditioner was required about 4 days to reduce the moisture content to about 10 %, keeping the quality of dried product at good grade. o. The optimum deposit-depth of the chopped seombody in the batch-type dryer used was about 28cm with about 42kg/hr of drying performance rate. However, it was necessary to overturn the materials between the upper and lower layers in order to obtain a good quality of dried product. d. The drying performance rate by the tunnel-type drier was highest among those of drying systems tested, giving the rate of approximately 400kg/day. 3. On reviewing the individual drying system for seombody, it was possible to draw conclusion that the best system was tunnel drying with the crushed seombody as far as the performance rate was concerned. However, the methods gives the highest operational cost. The system for the lowest operational cost with good quality of dried product was the sun-drying with the crushed material. Accordingly, it may be recommended that the system of sun-drying for the crushed seombody may be the most feasible system presently applicable to farm-level operation.

• 대한토목학회논문집
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• 제40권1호
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• pp.51-58
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• 2020

달 탐사에 대한 관심이 늘어나면서 인공월면토를 포함한 달 지상 환경 모사에 대한 연구가 진행되고 있다. 인공월면토를 포함하여 진공환경을 조성할 때 발생하는 문제점 중의 하나는 토양에서 나오는 탈 가스로 인해 고진공에 도달하는 시간이 길어진다는 것이다. 이러한 탈 가스의 대부분은 수분이며, 진공챔버에 넣기 전 인공월면토의 표면에 붙어있는 수분을 제거하는 전처리 과정을 수행한다면 고진공에 도달하는 시간을 상당히 줄일 수 있다. 기존의 토양 건조 방법을 사용하여 각 방법이 인공월면토의 수분제거에 얼마나 효과적인지 확인하였다. 드라이 오븐을 이용한 방법, 마이크로웨이브 오븐을 이용한 방법, 직접가열 건조하는 방법과 진공 오븐을 이용한 방법을 이용하여 인공월면토 시료의 건조 실험을 수행하였으며, 건조 실험의 결과를 제시하였다. 실험결과 드라이 오븐에서 110℃로 건조하는 방법과 마이크로웨이브 오븐을 이용한 건조 방법은 수분제거 효과가 충분하지 않았으며, 200℃ 이상에서 진공오븐을 이용한 방법과 직접 가열하는 방법은 수분제거 효과가 좋았다.

• 자원리싸이클링
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• 제27권1호
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• pp.106-117
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• 2018

본 연구는 수경성 무기재료를 사용한 배합의 고정수량 측정을 위해 적절히 사용할 수 있는 건조방법을 찾기 위해 수행되었으며, 제1보에서는 보통 포틀랜드 시멘트, 그리고 본 제 2보에서는 알칼리 활성 슬래그의 경우에 대해 다루었다. 다양한 w/b, 알칼리 활성화제 종류 및 양을 갖는 알칼리 활성 슬래그에 대해 진공건조 및 오븐건조, 이 둘의 조합 그리고 작열법이 사용되었다. 실험결과, 진공건조 후 오븐건조를 사용한 경우 비록 수화물의 결정수 일부가 분해되지만 자유수분의 완전한 증발이 가능하여 그 결과값의 편차가 작았으며, 따라서 AAS의 수화도를 정량평가하기 위한 단순하고 쉬운 고정수량 측정방법으로 적합하다고 판단하였다.

• 한국식품저장유통학회지
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• 제12권5호
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• pp.449-454
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• 2005

고품질의 지실을 포제하기 위한 건조법을 개발하기 위하여, 미성숙 탱자과실을 자연음건법, 적외선건조법, 동결건조법 등으로 건조하고 분말 및 추출액을 조제하여 이화학적 특성을 조사하였다. 동결건조 분말은 다른 건조법의 분말보다 L값, -a값, carotenoid, chlorophyll a 및 b 함량은 높았으나 naringin 함량은 유의적으로 낮았다. 적외선건조 분말은 자연음건 분말보다 L값, naringin, chlorophyll b 함량은 낮았으나 b값, carotenoid, chlorophyll a 함량은 유의적으로 높았다. 반면에 분말의 hesperidin 함량은 건조방법에 따른 유의적인 차이를 보이지 않았다. 추출수율은 에탄올보다 물 추출에서 높았으며 물 추출에서는 동결건조구에서 가장 높았으나 에탄올 추출에서는 건조방법의 영향을 보이지 않았다. 물 추출액은 에탄올 추출액보다 갈변도, 산도, 총당 함량은 유의적으로 높았으나 pH는 낮았다. 물 추출액의 산도는 적외선건조구에서, 총당은 동결건조구에서 각각 가장 높았으나 갈변도와 pH는 건조방법간에 유의적인 차이를 보이지 않았다. 한편, 에탄올 추출액의 갈변도, pH, 산도 및 총당 등은 건조방법의 영향을 보이지 않았다. 이상의 결과로 볼 때, 건조방법은 지실의 이화학적 특성에 상당한 영향을 미치며 자연음건보다는 동결건조가 고품질의 지실을 포제할 수 있는 방법으로 확인되었다.

• 한국식품과학회지
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• 제31권5호
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• pp.1283-1288
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• 1999

김의 분말화를 위한 최적조건을 결정하기 위하여 돌김과 참김을 천일건조, 열풍건조$(60,\;105^{\circ}C)$, 진공건조 및 동결건조방법을 사용하여 건조방법에 따른 김의 ascorbic acid함량과 김의 대표적인 색소인 chlorophyll, carotenoid, phycobilin의 변화를 조사하였다. 김의 chlorophyll, carotenoid, phycobilin은 김을 채취하여 수세, 건조하는 과정뿐만 아니라 건조방법에 의해서도 손실되는 양의 차이가 나타났다. 고온의 열풍건조는 김의 색소 보존 면에서 가장 좋지 많은 방법으로 나타났으며, 사용한 건조방법 중 동결건조가 가장 우수한 것으로 나타났다. 또한, vitamin C는 건조방법에 따라 75-99% 까지 손실되었다. 김분말의 등온흡습곡선들은 sigmoid형의 곡선을 나타했으며, BET식에 따라 결정한 단분자층 수분함량은 돌김과 참김분말 모두 6.30%(dry basis)이었다.50 mesh, 80 mesh, 100 mesh 체로 사별한 돌김 분말은 각각 80, $100{\sim}110$ 및 $110{\sim}120\;{\mu}m$를 중심으로 단일한 입도분포를 나타내어 김분말의 입자가 균일함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.357-364
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• 2016

Purpose: This study was performed to define the drying characteristics of sorghum by developing thin layer drying equations and evaluating various grain drying equations. Thin layer drying equations lay the foundation characteristics to establish the thick layer drying equations, which can be adopted to determine the design conditions for an agricultural dryer. Methods: The drying rate of sorghum was measured under three levels of drying temperature ($40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$) and relative humidity (30%, 40%, and 50%) to analyze the drying process and investigate the drying conditions. The drying experiment was performed until the weight of sorghum became constant. The experimental constants of four thin layer drying models were determined by developing a non-linear regression model along with the drying experiment results. Result: The half response time (moisture ratio = 0.5) of drying, which is an index of the drying rate, was increased as the drying temperature was high and relative humidity was low. When the drying temperature was $40^{\circ}C$ at a relative humidity (RH) of 50%, the maximum half response time of drying was 2.8 h. Contrastingly, the maximum half response time of drying was 1.2 h when the drying temperature was $60^{\circ}C$ at 30% RH. The coefficient of determination for the Lewis model, simplified diffusion model, Page model, and Thompson model was respectively 0.9976, 0.9977, 0.9340, and 0.9783. The Lewis model and the simplified diffusion model satisfied the drying conditions by showing the average coefficient of determination of the experimental constants and predicted values of the model as 0.9976 and Root Mean Square Error (RMSE) of 0.0236. Conclusion: The simplified diffusion model was the most suitable for every drying condition of drying temperature and relative humidity, and the model for the thin layer drying is expected to be useful to develop the thick layer drying model.

• 수산해양교육연구
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• 제29권3호
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• pp.888-898
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• 2017

Tenebrio molitor larvae, also known as yellow mealworms (MW), are rich in protein and lipid and can serve as a potential alternative protein and energy source in commercial aquafeeds. Therefore, this study attempts to evaluate the effects of different drying methods on the nutritional value of MW meal. For this, live MW were cold-anaesthetized before being subjected to three different types of drying methods, including freeze-drying, oven-drying at $60^{\circ}C$ and air-drying at room temperature for three days, and compared for proximate composition and energy content. An in-vivo digestibility test was then conducted to evaluate the nutrient digestibility of MW meal in diets for rockfish, Sebastes schlegeli. A test diet was prepared by mixing the MW meal with a reference diet (Ref) in a 30:70 ratio with chromium oxide as an inert marker at the inclusion level of 0.5%. Rockfish with mean body weight of 150 g were stocked into a fecal collection system equipped with fiberglass tanks of 400 L capacity. Each group of fish was fed one of the experimental diets to apparent satiation for 4 weeks. The results of the proximate analysis showed that drying methods had no significant effect on crude protein, crude lipid, ash and energy contents of MW. Despite being a rich source of protein and lipid, MW meal was deficient in certain amino acids, particularly methionine, and highly unsaturated fatty acids, particularly 22:6n-3 (DHA) and 20:5n-3 (EPA). MW meal showed high digestibility values for protein (93%), lipid (97%) and energy (88%). These results may indicate that MW meal is a nutritious and acceptable feed ingredient, with comparable digestibility values to conventional animal and plant feedstuffs such as fish meal and soybean meal, in practical diet for rockfish at grower stage.