• Journal of Advanced Marine Engineering and Technology
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• 제26권2호
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• pp.226-232
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• 2002

In tradition, there have been two kinds of drying methods, which are sun drying and artificial drying. The sun drying method which has been adopted traditionally has been replaced by the hot-air drying method which is one of the most general methods of artificial drying, with its simple drying system, low initial cost of drying plant, and easy operating method. But the hot-air drying method has some defects ; (1)much energy loss happens due to the discharge of hot air during the drying process, (2)control of drying rate is not easy on account of changing relative humidity of inlet air for uniform hot air temperature, (3)high temperature of floods in drying process brings about the production of low-grade drying products. Also, the hot-air drying method is inducing environmental and sanitary problems which are resulting from the emission of high temperature and high humidity air, including stick on the drying progress. Vacuum drying technique, whose drying time and 7uantity of exhausting energy is about 1/3 ~1/4 of hot air drying, is very excellent in the drying efficiency. As the results, it took about 20 hours for material to reach about 18% of the final moisture content in order to store products for a long time, from about 470% of the early moisture content at the beginning of drying, and maximum drying rate comes to about $0.35 kg/m^2hr$ at about 350% of the moisture content.

• 한국식품영양과학회지
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• 제25권3호
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• pp.453-459
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• 1996

This study was carried out to determine the changes in quality during the drying process and the optimum drying condition for utilizing soybean curd residue. The quality criteria for soybean curd residue were acid value, peroxide value, fatty acid composition and microbial concentration. The acid values of soybean curd residue were 7.5, 4.5 and 5.9 KOH mg/g upon 12 hour drying with open-air sun, ambient-air blast and warm-air blast, respectively. The numbers of total aerobic bacteria and molds increased remarkably during drying with open-air sunlight, ambient-air blast and warm-air blast except for hot air blast. Among different drying methods, the hot air blast drying(1kg of sample) was the most effective methods, which completed in three hours. Also, the drying method demonstrated a typical drying curve ; settling down, constant rate drying and falling rate drying period were shown within one hour, from one and three hours and after three hours, respectively. Moreover, there was significant variation in the constant drying period for the quality of soybean curd residue.

• Journal of Biosystems Engineering
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• 제25권2호
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• pp.89-96
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• 2000

In this study, experiments were performed for various drying air temperatures, air flow rates tray distance to analyze drying characteristics of batch type tunnel dryer. In comparison of tunnel drying with cabinet drying which is currently used in the farm, the results of drying simulation model of cabinet dryer was used and then the possibility of applying the drying simulation model of cabinet dryer to batch type tunnel dryer was investigated. The results showed that as the drying temperature increased, the drying rte and moisture difference in the direction of air flow increased and as the air flow rate increased, the drying rate increased and moisture differences decreased. In tunnel dryer, drying through bottom of the tray had large effect on drying rate and the effect was more significant when the drying temperature increased. As air flow rate increased, the difference of drying rates between tunnel and cabinet drying increased and drying rate of tunnel of drying was higher. The drying simulation model could estimate moisture content in tunnel more precisely by using modified effective moisture diffusion coefficient for air flow rate.

• Journal of the Korean Wood Science and Technology
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• 제13권3호
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• pp.27-33
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• 1985

Air-drying tests were carried out on green taun (Pometia pinnata f glabra) for 25-mm and 50-mm thickness to elucidate drying characteristics on air-drying rate, time and defects in spring and air-drying calendar. The results of this study were as follows: 1. The air-dried lumber for 25-mm thickness from an initial average moisture content (MC) of $58.3{\pm}3.5$ percent reached 30 percent MC in 17 days, 25 percent MC in 24 days, 20 percent MC in 38 days and 15 percent MC in 84 days. 2. The air-dried lumber for 50-mm thickness from an initial average MC of $59.6{\pm}5.0$ percent reached 30 percent MC in 39 days, 25 percent MC in 55 days and 20 percent MC in 84 days. 3. Air-drying calendar that could be useful in estimating drying times for each month developed by the use of climatological data for Suwon. Total number of effective air-drying days during a year were 243.5 days and the major determinant of the effect air-drying days was temperature. 4. The air-drying rates for 25-mm and 50-mm coated lumber were slight1y slower than those of uncoated lumber. The number and total length of both end checks and surface checks for end coated lumber were less severe than those of uncoated lumber.

• Journal of Biosystems Engineering
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• 제32권1호
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• pp.6-12
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• 2007

This study was conducted to investigate the drying characteristics of oak mushroom using stationary far-infrared dryer. Drying characteristics was measured at drying air velocity 0.4 to 0.6 m/s and drying temperature 50, 60, and 70$^{\circ}C$, respectively. With high temperature of far-infrared heater and fast air velocity, the far-infrared drying rate of double air flow system was better than conventional heated-air drying as much as 39%. The value of color difference (E) of oak mushroom before and after drying was 8.95 by using heated air drying and was in the range of 3.76$\sim$6.98 by the far-infrared drying. The shrinkage rate of oak mushroom after heated air drying was higher than that of air velocity, 0.6 m/s of far-infrared drying conditions, and was lower than that of air velocity, 0.4 m/s of far-infrared drying conditions. The content of free amino acid was higher in far-infrared drying than heated air drying.

• 한국약용작물학회지
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• 제14권1호
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• pp.8-13
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• 2006

삼백초의 유효성분과 선도유지에 적합한 건조방법을 구명하고자 건조방법을 달리하여 건조시킨 후 건조방법별 유효성분 함량과 선도를 조사한 결과를 요약하면 다음과 같다. 1. 건조방법별 건조시간은 양건에 비해 열풍건조와 동결건조시 $88{\sim}93%$ 단축되었다. 건물수율은 동결건조 > 양건 > 열풍건조 순으로 높았고, 건조후 수분 함량은 양건 > 열풍건조 > 동결건조 순으로 높았다. 2. 총페놀성 화합물과 quercetin 관련물질 함량은 동결건조 > 열풍건조 > 양건 순으로 높았으며, 열풍건조후 볶음 또는 건조전 증자 처리를 함으로써 감소되었다. 항산화 활성은 동결건조에서 가장 높았고, 열풍건조와 양건 간에는 차이가 없었으며, 열풍건조후 볶음 또는 건조전 증자 처리를 함으로써 증가하여 총페놀성 화합물과 quercetin 관련물질 함량과는 다른 경향을 보였다. 3. 적색도 (a)는 동결건조 < 열풍건조 < 양건 순으로 낮았다. 4. 열풍건조시 부위별 총페놀성화합물과 quercetin 관련물질 함량은 꽃 > 잎 > 세절 > 줄기 순으로 높았으며, 항산화 활성도 유사한 결과를 나타내었다. 부위별 적색도는 잎 < 세절 < 꽃 < 줄기 순으로 낮았다. 5. 삼백초의 유효성분과 선도유지에 적합한 건조방법은 세절하여 동결건조하거나 잎과 꽃만을 열풍건조하는 것이 효과적이었다.

• 한국농공학회지
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• 제17권4호
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• pp.3980-3990
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• 1975

This study was carried out to develop a method of grain drying ststem that can be done by forcing the heated-air directly into the grains within the sack. The air duct was pushed into the central position of the grain-deposited sack and the heated-air was forced to flow in the radial direction. The system is referred here as the unit sack drying system. At a first step of this study, an air flow resistance tester was constructed to measure the resistance of air flow to grains in cooperated with some different sack materials, the sack materials, the tested were rice-straw bag, sack of polyethylene film, and jute sack In addition, unit sack drying system was constructed to investigate the drying characteristics of the dryer. on this dryer, two kind of terminal air ducts were attached and tested to examine its effects on uniform drying, and also, aseries of drying test was performed to trace the effect of increasing air flow rate on uniform drying. The results are as follows: 1) Resistance of air flow for each sack material was increased almost proportional to the increasing rate of air flow. Experimental data showed little significant differences of the air flow resistance among the materials. 2) From the comparison with air flow resistance of sack material and that of roughrice, it was indicated that airflow resistance of sack material was much higher than that of rice rough Therefore, in the unit sack drying sysle in which air flow is destined to face the sach material after leaving the grain, it was suggested that air flow would be inuniform to each part of grain within sack because of much higher air flow resistance of sack material than that of grain, and the fact would results inuniform grain drying. 3) Drying test on the unit sack drying system in cooperated with different type of terminal air ducts showed that high speed air is better for uniform drying than in high pressure. with the drying system which was assembled with the air ducts delivering higher speed air, there also involved a problem of significant inuniform drying. Therefore, any means to improve the inuniform drying should be undertaken for practical use. 4) A series of drying test with in creasing air flow rate resulted that increasing air flow rate in the unitsack drying system gave little effect on uniform drying, therefore, it is recommened to change its drying system for drying grain uniformly.

• Journal of Biosystems Engineering
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• 제34권3호
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• pp.175-182
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• 2009

This study was conducted to investigate the drying characteristics of tissue cultured mountain ginseng roots. The far infrared rays dryer of a double blast system used for this experiment can control the drying parameters such as far infrared heater temperature and air velocity. The far infrared rays drying tests of tissue cultured mountain ginseng roots were performed at air velocity of 0.4, 0.6, 0.8 m/s, under drying air temperature of 50, 60, and $70^{circ}C$, respectively. The results were compared with one obtained by the heated air drying method. The drying characteristics such as drying rate, color, energy consumption, saponin components and antioxidant activities were analyzed. The results showed that the drying rate of far infrared rays drying was faster than that of heated air drying and due to high temperature of drying air and fast air velocity, the far infrared rays drying of double blast type was superior to the heated air drying. The value of the color difference for heated air drying was 10.11${\sim}$12.99 and that of far infrared rays drying was in the range of 7.05${\sim}$7.54, which was in the same drying condition, also energy consumption of far infrared rays drying was in the range of 3575${\sim}$6898 kJ/kg-water. At the same time, the antioxidant activities using far infrared rays drying were higher than those using heated air drying.

• 한국식품과학회지
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• 제38권5호
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• pp.635-641
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• 2006

본 연구에서는 자연건조 및 온풍건조에서의 문제점을 보완하고자 냉풍건조공정을 이용하여 말린 오징어의 품질 특성을 비교 하였다. 건조속도는 온풍건조가 15시간만에 목적하는 수분함량에 도달하여 가장 단시간에 건조가 완료되었으며 자연건조, 냉풍건조 순이었는데 $7^{\circ}C$ 냉풍건조가 건조시간이 165시간으로 가장 많이 소요되었다. 건조방법과 건조온도에 따른 ${\Delta}E$ 값은 자연건조가 57.78로 색의 변화가 가장 컸으며, 물성은 냉풍건조가 다른 간조방법에 비해 조직감이 우수하였다. TBA 가는 건조시간 및 온도가 증가할수록 높아지는 경향이었고 총아미노산 및 지방산 함량은 냉풍건조 $15^{\circ}C$가 다른 건조방법에 비해 우수하였다. 콜레스테롤 함량은 온풍건조 $30^{\circ}C$에서 488.5 mg/100 g으로 가장 많이 감소하여 건조조건이 마른오징어의 콜레스테롤 함량에 많은 영향을 끼침을 확인하였다. 종합적인 기호도는 지질의 산화에 의한 향미 변화와 갈변의 발생정도가 낮은 $15^{\circ}C$ 냉풍건조가 가장 우수하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.242-247
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• 2009

The present study has been conducted to reduce the cold air drying rate. According to the cold air drying method, the quality-excellent product could be made and there would be little change of color, taste and smell. As compared with the hot air drying, the cold air drying equipment has the superior dehumidification in a constant drying zone. However, in a falling drying zone that equipment is not energy-efficient because the drying period could be longer by the dehumidificated.