• 설비공학논문집
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• 제16권10호
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• pp.923-931
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• 2004

A multi-dimensional freeze drying analysis program, which took simultaneous heat and mass transfer, sublimation of ice and motion of sublimation front into full account, was developed using finite volume method with fixed grid. The effect due to the motion of sublimation interface was modeled by an enthalpy formulation streamlined for the freeze drying problems. The efficiency and accuracy of the program was validated by solving one- and two-dimensional freeze drying problems frequently encountered in industrial processes. Finally, the freeze drying processes of cylinder and slab objects with permeable side surfaces were simulated, which demonstrated the capability of the present analysis program in solving multi-dimensional freeze drying problems with complex sublimation interface configurations.

• Nutrition Research and Practice
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• 제6권3호
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• pp.187-194
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• 2012

In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization.

• 한국식품영양학회지
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• 제9권3호
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• pp.271-274
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• 1996

New drying method was tested for the Quality control for Kwamegl, dry Pacific saucy(Cololahis saira) In east coast area of Kyungbuk province, Korea. Cholesterol content of raw fish was 56% on dry basis, and decreased to 50.82 mg% rapidly the first 3 day and then, it was almost unchanged. However, the cholesterol content decreased slowly to 52.3 mg% during 15 days in new artificial drying.

• 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.

• 한국식품영양과학회지
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• 제39권9호
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• pp.1353-1358
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• 2010

폐자원으로써 버려지는 포도 가공부산물의 활용을 위한 기초연구로 본 연구에서는 포도부산물의 건조방법에 따른 일반성분, 색도, pH, 항산화성분 및 활성을 비교분석 하였다. 일반성분의 경우, 회분, 조지방, 조단백 함량은 열풍건조시료에서 더 높은 함량을 나타내었다. 색도 측정결과, L값(명도)과 a값(적색도)은 동결건조 한 시료가 더 높게 나타난 반면, b값(황색도)의 경우 열풍건조시료에서 높은 값을 나타내었다. pH는 열풍건조시료의 pH가 동결건조시료에 비해 약간 높은 값을 나타내었으나 큰 차이는 보이지 않았다. 총 폴리페놀 함량 및 안토시아닌 함량은 동결건조시료에서 더 높은 함량을 나타내었다. 항산화 활성 측정 결과 라디칼 소거능의 경우, DPPH 및 ABTS 라디칼 소거능이 열풍건조시료에 비해 동결건조시료에서 비교적 우수한 활성을 나타내었다. 반면, 환원력으로 측정한 항산화 활성의 경우, reducing power 및 FRAP 값이 동결건조시료에 비해 열풍건조시료에서 높은 활성을 나타내었으나 수치상으로 큰 차이를 보이지는 않았다. 이상의 결과에서 건조방법에 따른 항산화 성분과 항산화 활성을 비교한 결과 열풍건조시료에 비해 동결건조 시료가 더 우수한 것으로 사료된다.

• Journal of Biosystems Engineering
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• 제29권1호
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• pp.37-44
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• 2004

This study was conducted to develop a new drying method far reducing the drying cost and time and to investigate the drying characteristics of oak mushroom. A far infrared dryer of down draft air flow type used for this experiment can control the drying parameters, such as far infrared heater temperature and aeration velocity. The far infrared drying tests were performed at aeration velocities of 0.3 and 0.6m/s under the temperature of 90 and 100$^{\circ}C$ in for infrared heater, respectively. The results were compared and analyzed with those of an heated air drying method used as a control in terms of properties representing the drying characteristics. such as shrinkage rate, color, energy consumption amino acid components, drying rate and moisture ratio. The results obtained from this research can be summarized as follows. 1. The drying rate of far infrared drying was faster than that of heated air drying. With high temperature of far infrared heater and slow aeration velocity, the far infrared drying of down draft air flow type was superior to the heated air drying. 2. Most of far infrared drying conditions required less energy consumption than heated air drying. 3. The shrinkage rates of heated air drying and far infrared drying were decreased by 17.0% and 18.2∼19.8%, respectively. 4. The difference of color on oak mushroom surface before and after drying can be represented as $\Delta$E. $\Delta$E values of far infrared drying and heated air drying were 2.39∼4.55 and 6.77, respectively. 5. The amounts of free amino acids were higher in the far infrared than in the heated air drying. In addition the amounts of Gln and Glu generally were increased and those of Ala, Leu, and Val were decreased in order.

• 한국응용과학기술학회지
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• 제28권3호
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• pp.367-373
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• 2011

This research is a basic researching process for producing solid fuel that mixing paper sludge and Heat Transfer Medium Oil. Under the presence of Heat Transfer Medium Oil, paper sludge is heated and dried with home appliance microwave for comparing drying efficiency and energy efficiency of different types of drying method. As a result, Heat Transfer Medium Oil and paper mixing case of drying method, OMD, is the most efficient way to shorten the time for evaporating moisture in the paper sludge. In addition, heat transfer effect and density is increased with adding Heat Transfer Medium Oil by microwave. Future more, OMD's energy cost for evaporating whole moisture is 78% cheaper than MD. Also, OMD process shows the best energy efficiency with comparing other process. Evaporation rate of paper sludge evaporation process with microwave is 11.66% increased by adding Heat Transfer Medium Oil 150g. Preheating Heat Transfer Medium Oil or improving different ways injecting Heat Transfer Medium Oil is a good way to increase a rate of initiative moisture evaporation process.

• 한국식품저장유통학회지
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• 제12권5호
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• pp.417-423
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• 2005

본 연구에서는 마른 오징어의 품질 향상을 위해서 일반적으로 많이 사용되고 있는 천일 건조와 온풍건조 방법을 이용하여 건조조건에 따른 마른 오징어의 건조특성 및 이화학적 품질 특성을 분석하였다. 건조방법에 따른 건조완료 마른오징어의 건조시간, 수분함량 및 수분활성도는 온풍건조의 경우 온도가 증가함에 따라 건조시간은 줄어들었고 천일건조의 경우에는 총 120시간만에 건조가 완료되었으며 수분활성도는 미생물의 생육과 증식이 불가능한 0.468~0.486을 나타내었다. 마른오징어의 $\Delta$Ε 값은 같은 온풍건조 30$^{\circ}C$를 제외하고 차이가 적어 육안으로는 큰 차이를 느끼지 못하였다. 건조 방법 및 시간에 따른 TBA가는 차이를 보여 건조 완료 마른오징어의 경우 35℃ 온풍건조가 가장 높게 나타났다. 오징어의 맛을 내는 아미노산인 proline, alanine, glycine과 taurine은 온풍건조 35$^{\circ}C$에서 가장 높았으며 천일건조의 경우 생오징어와 유사한 조성비를 가지고 있었지만 유리 아미노산의 양은 감소한 것으로 나타났다. 천일건조와 온풍건조를 비교하면 총 지방산의 함량은 천일건조가 많은 것으로 나타났으며, 콜레스테롤 함량은 생오징어가 707.8 mg/100 g, 천일건조는 522.3 mg/100 g, 온풍건조는 평균 511.4 mg/100 g로 나타나 건조 오징어의 콜레스테롤 함량이 감소하는 경향이었다.

• 대한약침학회지
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• 제21권2호
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• pp.112-119
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• 2018

Contents of compounds in Rehmanniae Radix change depending on the number of steaming and drying and the drying method. In this study, as an impregnation method for dried Rehmanniae Radix, takju impregnation and cheongju impregnation were carried out and steaming and drying were repeated for 9 times. The changes of 5-HMF and catalpol contents were analyzed according to the number of repetition times to investigate which stage of steaming and drying is preferable. Also, total nitrogen, crude fat, ash, and crude fiber were measured to analyze changes in general components. 5-HMF was not detected in dried Rehmanniae Radix. As a result of repetitive steaming and drying, the content of 5-HMF increased only slightly from 1 to 4-times steaming and drying but increased significantly from 5-times. The catalpol in dried Rehmanniae Radix was not detected after 5 times of steaming and drying. Sucrose, maltose, and glucose were included in dried Rehmanniae Radix before steaming and drying. However, after the process in both Takju impregnation and Cheongju impregnation, galactose and fructose tended to decrease after production and sucrose and glucose tended to decrease after the increase. In this study condition, 6-times and more steaming and drying were appropriate process which met the content criteria (not less than 0.1%) of the Korean Pharmacopoeia (8th edition) for 5-HMF, an index component for quality control of Rehmanniae Radix Preparata.

• Journal of Biosystems Engineering
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• 제23권3호
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• pp.229-244
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• 1998

This study was performed to determine proper fan and heater management schemes for natural air drying of rough rice in round steel bin with stirring device under Korean weather conditions. A computer simulation model was developed to predict moisture content changes, energy requirements, and drymatter losses during drying of rough rice by natural air. Drying test was conducted to validate the simulation model using round steel bin of holding capacity of 300ton at Rice Processing Complex in Jincheon. The bin was filled with rough rice every day and mixing by stirring device. Moisture contents, ambient air temperatures, relative humidities, static pressures in plenum chamber in the bin, airflow rates, and electrical and fuel energy were measured. Relative errors of moisture content changes predicted by the simulation model were below 5ft, and relative errors of final moisture content, final grain weight, required energy ranged from 0.9% to 6%. These not levels indicated that the simulation model can satisfactorily predict the performance factors of natural air drying system such as drying rates and energr consumptions comparing error level of 10% to 15% in other drying simulation models generally used in dryer desists. Twelve different fan and heater management schemes were evaluated using the computer simulation model based on three hourly weather data from Suweon for the period of 1952-1994. The best management schemes were selected comparing the drymatter losses, required drying times, required energy consumptions. Operating fan without heating only when ambient relative humidity was below 85% or 90% appeared to be the most effective method of In operation in favorable drying weather. Under adverse drying climates or to reduce required drying time, operating fan continuously, and heating air with $1.5^{\circ}C$ temperature rise only when ambient relative humidity was over 85% appeared to be the most suitable method.