• 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.

• 한국조리학회지
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• 제19권4호
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• pp.13-24
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• 2013

본 연구는 냉동오디를 냉동건조와 열풍건조 방법으로 건조 후 분말화하여 마들렌에 첨가하여 제품의 품질 특성을 알아보고자 하였다. 냉동건조와 열풍건조로 냉동오디를 건조 후 분말화하여 각각의 시료의 일반성분과 이화학적 특성을 측정하여 비교 분석하였다. 마들렌은 제과기능사 실기시험에 출제되는 레시피를 토대로 각각의 시료를 밀가루 양에 대비하여 0%(control), 1%, 3%, 5%, 7%를 첨가하여 만들어 pH, 색도, 텍스쳐를 측정하고 관능검사를 통하여 소비자의 기호도를 파악하였다. 먼저 pH는 열풍건조오디분말 첨가군이 낮게 나타났으며, 색도에서 명도(L값)는 냉동건조오디분말과 열풍건조오디분말의 첨가율이 증가할수록 대조구와 비교해 감소하는 경향이 나타났다. 적색도(a값)는 열풍건조오디분말을 첨가했을 때가 냉동건조오디분말을 첨가했을 때보다 적색도가 증가하는 것으로 나타났다. 황색도(b값)는 오디분말의 첨가량이 증가할수록 감소하는 경향을 나타내었다. 냉동오디분말 첨가군은 경도(Hardness)와 탄력성(Elasticity)은 오디분말의 첨가량의 증가에 따라 유의적인 차이가 나타났다. 응집성(Cohesiveness)과 검성(Gumminess)은 첨가량이 증가함에 따라 감소하는 경향이 나타나고 있다. 열풍건조오디분말을 첨가한 마들렌의 경도(Hardness)는 오디분말 첨가량에 따라 유의적인 차이를 나타내었다. 탄력성(Elasticity)은 오디분말 첨가량에 따라 증가하며, 응집성(Cohesiveness)은 첨가량이 줄어들수록 감소하는 경향을 보였다. 검성(Gummines)은 첨가량이 증가할수록 증가하는 경향을 나타내었다. 관능검사의 기호도 결과는 냉동건조오디분말 5% 첨가군과 열풍건조오디분말 7% 첨가군의 기호도가 가장 높게 나타났다.

• Journal of Ginseng Research
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• 제16권2호
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• pp.111-123
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• 1992

Drying characteristic data for peeled ginseng were obtained to determine dominant drying factors and fitted with five selected drying models and an empirical model. Among air temperature, relative humidity and diameter of ginseng root, drying air temperature was found to be the most influencing factor on drying rate. Drying velocity appeared faster as the drying temperature increased but its effect was less at high temperature than at low temperature. Quality change during the drying process did not occur except when relative humidity was 75fb. At high relative humidity, skin color of ginseng was turned to light brown. Approximate-Diffusion and the Empirical model for drying were in a good agreement with experimental data. The models are as follows; $.$ Approximate-Diffusion model MR = A$.$exe(-k$.$1) A = 1.72 + 0.407 In(D) - 0.0000963T3 - 0.358 In(RH) + 0.0000945 RH2 B= 1.01 + 0.0195RH - 0.O0518D2 + 0.0708 In(T) - 0.492 In(RHI-D.0000933RH2$.$Empirical model MR= Cl + Cs$.$In(t) Cl= 1.14+0.382 In(D)-0.00008477a-0.139 In(RH)+0.0000664RH2 Cs=0.440-0.0224 In(D)-0.193 In(T)+0.0000464T2-0.00000771RH2

• Journal of Biosystems Engineering
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• 제27권1호
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• pp.45-50
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• 2002

This study was performed to develop thin layer drying equations fur short grain rough rice using far-infrared ray. Thin layer drying tests was conducted at four far-infrared ray temperature levels of 30, 40, 50, 60$^{\circ}C$ and two initial moisture content levels of 20.7, 26.2%(w.b.). The measured moisture ratios were fitted to Lewis and Page drying models by stepwise multiple regression analysis. Half response time of drying was affected by both drying temperature and initial moisture content at drying temperature of below 40$^{\circ}C$, but at above 40$^{\circ}C$ was mainly affected by drying temperature. Experimental constant(k) in Lewis model was a function of drying temperature, but K and N in Page model were function of drying temperature and initial moisture content. Moisture ratios predicted by two drying models agreed well with experimental values. But in the actual range of drying temperature above 30$^{\circ}C$ Page model was more suitable for predicting of drying rates.

• 동아시아식생활학회지
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• 제16권2호
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• pp.180-185
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• 2006

To develop a new instant pumpkin gruel food, this study investigated the dried powder and gruel quality characteristics depend on drying method. The pumpkin powder was dried by infrared and freeze drying, and then milled to 80 mesh, after which the manufactured gruel was mixed with glutinous rice by heating. The gruels prepared by dried pumpkin powder were compared with steamed and freeze dried powder as a control, the crude protein and total sugar contents were high in the infrared drying powder, but freeze drying kept more carotenoid content. Soluble solid of gruel was higher in the freeze dried powder, and steam treated powder showed increased L and b values. Sensory test was carried out to select proper drying methods with 5-point scale. The gruel with freeze dried powder gained the highest score in overall quality. These results suggest that freeze drying could be used for manufacturing high quality instant pumpkin gruel.

• 한국식품과학회지
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• 제25권5호
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• pp.558-564
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• 1993

쌀보리를 시료로 하여 건조조건을 다르게 하여 유동층 건조특성에 영향을 미치는 외부요인에 대해서 조사한 결과를 요약하면 다음과 같다. 쌀보리의 유동층건조는 항률건조기가 없이 감률건조 1단계, 감률건조 2단계의 두 단계로 일어남을 알 수 있었다. 또한 건조속도상수는 충전량이 적을수록, 공기속도가 클수록, 공기온도가 높을수록, 상대습도가 낮을수록 켰으며, 감율건조단계에서의 건조속도상수는 Arrhenius형의 plot에서 좋은 직선관계를 나타내어 이 단계가 활성화 과정임을 알 수 있으며, 감률건조 제 1단계의 활성화 에너지는 1900ca1/gmol, 감률건조 제 2단계의 활성화 에너지는 2500ca1/gmol을 각각 나타내었다.

• Journal of Biosystems Engineering
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• 제8권2호
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• pp.62-68
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• 1983

This study was to examine the drying characteristics of barley and the effect of moisture content of barley on milling performance. A barley variety, Jogang, having 35.0% of initial moisture content was used for this experiment. Thermo-hydrostatic dryer which consists of blower, condensor, heater, humidifier, drying chamber and control box, etc., was used for the drying experiment. The change in the weight of a barley sample was continuously measured by means of the ring type load cell installed inside the drying chamber. Milling test runs the samples having the predetermined moisture content were taken from each drying test run. A laboratory type barley miller was used for the milling test. The results of the study are summarized as follows: 1. The drying constants (k) applied for the thin layer drying model, (M-Me)/(Mo-Me) = $Ae^{-kt}$ were 0.155, 0.259 and 0.548, respectively, at the three levels of drying temperatures, $40^{\circ}C$, $50^{\circ}C$ and $60^{\circ}C$. The drying constants complied with the Arrhenius Equation, K = Ko exp (-C/T), were determined as $Ko=1.901455{\times}10^8$ and C = 6563. 2. The laboratory milling test indicated that the highest milled and head barley recovery was resulted from the sample which was dryed at $40^{\circ}C$. In general, the increase in the drying temperature from $40^{\circ}C$ to $60^{\circ}C$ indicated a negative effect on milling yields. 3. Also, the sample having 15% M.C. presented the highest milled and head barley recovery among the five moisture content levels (12, 15, 18,21 and 24%).

• 한국식품저장유통학회지
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• 제12권5호
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• pp.436-441
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• 2005

복분자의 포제에 있어 건조방법이 추출특성에 미치는 영향을 규명하기 위하여 생복분자 딸기를 5분간 증자하고, 자연 양건, 적외선 건조 또는 동결건조한 다음 20 mesh 크기로 분쇄하고, 열수나 40% 에탄올(80$^circC$)로 3시간 추출한 후 추출액의 이화학적 특성 및 항산화성을 조사하였다. 가용성 고형분과 총당의 추출수율은 동결건조품에서 가장 높았고 다음으로 적외선 건조품, 양건품 순이었으며, 건조법에 무관하게 에탄올보다는 물 추출액에서 높게 나타났다. 유기산의 추출수율과 추출액의 pH는 물 추출에서는 건조방법별 차이가 없었으나 에탄올 추출에서는 동결건조품에서 다소 높고 낮은 경향을 보였다. 총페놀의 추출수율과 추출액의 유리기 소거능은 동결 건조품, 적외선 건조품, 양건품 순이었으며, 물보다 에탄올 추출에서 높게 나타났다. 동결건조품에서 L값은 가장 높았고 a와 b값은 가장 낮았으며, 물보다 에탄올 추출에서 L과 b값은 높았으나 a값은 낮게 나타났다. 이로써 복분자 포제에 있어 전통적 자연 양건보다는 적외선 및 동결건조 특히, 동결건조의 적용에 의해 품질향상이 가능하며, 또한 총가용성 성분의 추출에는 물 추출이, 항산화성 성분의 추출에는 에탄올 추출이 유리한 것으로 확인되었다.

• 한국식품조리과학회지
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• 제27권1호
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• pp.75-84
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• 2011

The aim of this study was to develop a convenient brown sauce product with long shelf life that has similar taste and quality characteristics with sauce used in restaurants. Response surface analysis was carried out to optimize brown sauce. Extracted brown sauce powder was subjected to hot air drying, infrared drying, freeze drying, and spray drying to determine the appropriate drying method for brown sauce manufacturing. The optimum extraction conditions were set by superimposing and reading each reaction surface that satisfied all of the sensory characteristics such as color, smell, taste, concentration, and overall preference level in order to set the optimum conditions for brown sauce production. The optimum extraction conditions for brown sauce were determined to be heating time 30 min, gelatin addition quantity 9.00%, and tomato paste addition quantity 11.25%. Reliability test showed a similar value to the predicted scope when compared to the experimental value obtained under the same conditions as the predicted value according to RSM (response surface methodology), enabling verification of the derived regression formula. Product powder of ideal brown sauce by heating, infrared radiation, freezing, and spray drying and investigate result for functional tests of color, flavor, taste, viscosity, overall acceptability and show highly acceptability on powder by infrared rays and freeze-drying methods. Especially, infrared radiation method resulted in favorable color and flavor values while freeze-drying method produced good taste and viscosity values and high overall acceptability. Therefore, infrared radiation drying method and freeze-drying method to product powder.

• Journal of the Korean Wood Science and Technology
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• 제24권2호
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• pp.46-54
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• 1996

This study was carried out to investigate the vacuum drying characteristics of 50mm- and 75mm- thick tree disks of some domestic softwoods for substituting the conventional hardwoods as the materials for wood crafts. Though the elapsed drying times from green to in-use moisture content(MC) were largely shortened by vacuum drying, the tree disks treated by EWS couldn't be dried to in-use MC, and so sapwood stains also were occurred severely. We suggest EWS treatment is undesirable for the species with very high sapwood portion or vacuum drying with hot water circulation heating system. Heart checks were slight, but sapwood checks, which have never been trouble in drying process of tree disks, were severe. For the reasonable explanation it is suggested MC differences between sapwood and heartwood were large and most of tree disks had already no barks before drying test. Ginkgo was vacuum-dried with very slight drying defects such as heart checks, sapwood checks. V-cracks and sapwood stains. In Korean red pine and pitch pine V-cracks were severely occurred. And it was found the special feature that most of these defected tree disks contained several V-cracks within one tree disk. It can be considered as the causes that the region of sapwood was defected by the several checks at the early drying stage because of the steep MC gradient along the radial direction, and then at the later drying stage the drying stresses due to differential shrinkage were concentrated on these brittle spots.