• Title, Summary, Keyword: drying

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Changes in Days to Drying and Some Chemical Components by Different Drying Methods in Paeoniae radix (건조방법에 따른 작약근 건조 소요일수 및 성분 변화)

  • ;Kwang-He Kang
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.41 no.3
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    • pp.362-369
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    • 1996
  • Seven different drying methods were tested in peony roots of Euisung cultivar, harvested in February, in three year's old plant. The roots were selected in length and diameter and half of the samples were removed cork-layers to compare the effects of cork-layer in processing of drying. The 3$0^{\circ}C$ heat drying without cork-layer reduced in days to drying by five days compared to those of the with cork-layers at the same temperature. The 5$0^{\circ}C$ heat drying after cork-layers removed was the most effective in days to drying. In quality of skin color of the 5$0^{\circ}C$ heating was worse to compare with the lower drying temperature. In the drying at room temperature and the heat drying at lower temperature, the paeoniflorin content in drying after cork-layers removed were higher than that of the drying with cork-layers. However, in the boiling water treatment, the paeoniflorin contents in drying after cork-layers removed were lower than those of with cork-layers. In heat drying, paeoniflorin content showed a decreasing tendency to increase of drying temperature. Total sugars in the peony roots showed a decreasing tendency according to the drying temperature increasing, but starch concentration showed a increasing tendency at the same condition. Concentrations of crude protein, crude fiber and crude ash were showed no differences in various drying methods and the materials with or without cork-layers. Relationships between the paeoniflorin and total sugars, and the paeoniflorin and starch were different significantly by the materials of cork-layers removed or not. The 30~4$0^{\circ}C$ heat drying without cork-layers was the most advisable condition for drying in paeoniflorin concentration, days to drying and skin color after drying.

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Quality Characteristics of Ginseng Treated by Hot Air Drying after Being Dried using Super-heated Steam (초급속 과열증기를 이용한 인삼의 품질 특성)

  • Kim, Kyung-Tack;Hong, Hee-Do;Kim, Sung-Soo
    • Journal of Ginseng Research
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    • v.33 no.4
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    • pp.361-366
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    • 2009
  • This research aims to develop a new drying technology using super-heated steam to reduce the time required for drying ginseng and to enhance its quality. The drying rate of ginseng powder treated with hot-air drying after drying with super-heated steam was about 40% faster than the drying rate of ginseng powder treated with hot-air drying. Minimal difference was found between hot-air drying and hot-air drying after drying with super-heated steam in the general composition of the ginseng powder, such as its crude lipid, crude protein, crude fiber, and ash. Moreover, no difference was found between hot-air drying and hot-air drying after drying with super-heated steam in terms of the ginseng powder's mineral and free sugar contents. The crude saponin contents was 5.43% in the ginseng treated with hot-air drying and 5.4% in the ginseng treated with hot-air drying after drying with super-heated steam. The ginseng powder that was treated with hot-air drying after drying with super-heated steam had a slightly higher redness compared to the ginseng powder that was treated with hot-air drying alone. The number of microorganisms of the ginseng powder treated with hotair drying after drying with super-heated steam showed a reduction of one log cycle in the total bacteria and two log cycles in the yeast molds compared to the ginseng powder treated with hot-air drying alone.

Drying Characteristics of Oak Mushroom Using Conveyer Far Infrared Dryer - Down Draft Air Flow Type - (컨베이어 원적외선 건조기를 이용한 표고버섯의 건조특성 - 하향 송풍방식 -)

  • 연광석;김민호;한충수;조성찬;강태환;이해철;김창복;김진국
    • Journal of Biosystems Engineering
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    • v.29 no.1
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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.

Monitoring the Wood Drying Process with an Image Processing System (I) : Drying Characteristics of Tree Disk of Black Locust

  • Lee, Hyoung-Woo;Kim, Byung-Nam
    • Journal of the Korean Wood Science and Technology
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    • v.29 no.3
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    • pp.21-26
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    • 2001
  • Acquisition of precise information on drying characteristics of wood is indispensable for the improvement of drying schedules and wood quality. Recognition of the exact moisture content at which drying defects such as checks occur during drying with given drying conditions may be essential to reduce drying losses. In this study an image-processing system was combined with a laboratory-scale wood dry kiln for experiments and the surface of tree disk of black locust (Robinia pseudoacacia L.) was monitored to investigate the behavior of check formation over all the drying process. This system showed good potential for improving drying schedules and wood product quality.

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Numerical Analysis of the Drying Process of Sized Yarn (가호사 건조과정 해석에 대한 연구)

  • 사종엽;이제철
    • Textile Science and Engineering
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    • v.40 no.5
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    • pp.446-450
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    • 2003
  • The present study investigates the heat and mass transfer in the drying of sized yarn by using Luikov equation. The finite difference method is used to solve numerically the governing equation. The mass transfer rate in the drying process is influenced by environmental temperature and moisture. The Soret effect shows that the drying efficiency of sized yarn may be improved not only by increasing the temperature but also by decreasing the moisture content of air in the drying chamber. To check the accuracy of the present computational method, the drying process of timber has been solved and compared with previous results. The properties of starch was used in computing the drying process of sized yarn. The present study may help in finding the optimum conditions of the drying chamber as well as expanding the study to coupling of the drying process and the thermo-fluid flow dynamics in drying chambers.

Drying Characteristics of Rough Rice in Continuous Dryer

  • Song, D.B.;Koh, H.K.;Keum, D.H.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.863-877
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    • 1996
  • A drying model to predict the drying process in continuous dryer was developed and proved by drying experiments. The experiment showed that the difference of moisture contents between the predicted and the observed was within 0.5%(wb). There was no cracked rice found even in high drying rate with the inlet moisture content over 23%(wb), and tempering treatment in the same temperature reduced the ratio of cracked rice. There was a little difference in the ratio of cracked rice between 40$^{\circ}C$ and 45$^{\circ}C$ drying temperatures with the final drying moisture content (14.5% wb), and the cracked rice increased at 55$^{\circ}C$. As a results, it was better to make fast drying on the rice over 23%(wb) inlet content it was recommended to keep drying at 45$^{\circ}C$.

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Low Temperature Drying Simulation of Rough Rice (벼의 저온건조 시뮬레이션)

  • Kim, Hoon;Han, Jae-Woong
    • Journal of Biosystems Engineering
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    • v.34 no.5
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    • pp.351-357
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    • 2009
  • This study was conducted to verify the simulation model through the drying test, and investigate effect of factors, such as temperature of drying air, airflow rate, and velocity of the airflow, on the drying. The low temperature drying simulation model was developed based on the circulation dry simulation model presented by Keum et al. (1987), and by modifying low temperature thin layer drying model, equilibrium moisture content model, latent heat of vaporization model, and crack ratio prediction model. The heat pump and experimental dryer with a capacity of 150kg were used for the test. The RMSE between the predicted and measured value was 0.27% (drying temperature), 0.15% (crack ratio), and 2.08% (relative humidity), so the relevance of the model was verified. In addition, the effect of drying temperature, airflow rate, and velocity of the airflow on the drying was examined. The experimental results showed that the crack ratio at drying temperature of $25{\sim}40^{\circ}C$ was allowable. Moreover, at below $30^{\circ}C$, variation of the crack ratio was slight, but drying time was delayed. Given these results, the drying temperature of over $30^{\circ}C$ was effective. As the airflow rate increased, required energy dramatically increased. Whereas drying rate slowly increased, so loss of drying efficiency was caused. Considering these results, the dryer needed to be designed and adjusted to lower than $30\;m^3/min{\cdot}ton$. As velocity of the airflow increased, required drying energy increased when the velocity of the airflow was over $5\;m^3$/hr, while crack ratio and drying rate showed little variation.

Studies on the Drying Methods of Sea Foods 1 . Fixed Bed Drying of Squid (수산식품의 건조방법에 관한 연구 1 . 오정어의 고정층건조)

  • HUR Jong-Wha
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.15 no.1
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    • pp.107-110
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    • 1982
  • Fixed bed drying method was selected to reduce the initial drying time of squid and the effects of drying air temperature and bed height on the drying rate were investigated, with following results. 1. The drying rate in the fixed bed dryer was faster than that of natural convection type dryer heated indirectly and that of hot air dryer heated directly. 2, Shirai-equation was applicable to squid being dried. Using the equation, drying rate constant obtained was as shown in table 1.

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A Study on Drying Models of Ginseng (인삼의 건조모델에 관한 연구)

  • 최병민
    • Korean Journal of Food Preservation
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    • v.3 no.1
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    • pp.39-53
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    • 1996
  • Ginseng, one of the important economic crops, is processed into medicine, teas, beverages and even foods. Drying is the most important and burdensome work in the processing of ginseng, so development of ginseng dryer is needed for efficient drying and good quality of ginseng. Investigation of drying model is essential for development of ginseng dryer. Drying models for peeled ginseng were investigated to determine dominant drying factors and fitted with five selected drying models and an empirical model. Thompson and the empirical model showed best fit with the experimental data. Pother experiment is necessary to prove the superiority of the empirical models.

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Predictive Thin Layer Drying Model for White and Black Beans

  • Kim, Hoon;Han, Jae-Woong
    • Journal of Biosystems Engineering
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    • v.42 no.3
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    • pp.190-198
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    • 2017
  • Purpose: A thin-layer drying equation was developed to analyze the drying processes of soybeans (white and black beans) and investigate drying conditions by verifying the suitability of existing grain drying equations. Methods: The drying rates of domestic soybeans were measured in a drying experiment using air at a constant temperature and humidity. The drying rate of soybeans was measured at two temperatures, 50 and $60^{\circ}C$, and three relative humidities, 30, 40 and 50%. Experimental constants were determined for the selected thin layer drying models (Lewis, Page, Thompson, and moisture diffusion models), which are widely used for predicting the moisture contents of grains, and the suitability of these models was compared. The suitability of each of the four drying equations was verified using their predicted values for white beans as well as the determination coefficient ($R^2$) and the root mean square error (RMSE) of the experiment results. Results: It was found that the Thompson model was the most suitable for white beans with a $R^2$ of 0.97 or greater and RMSE of 0.0508 or less. The Thompson model was also found to be the most suitable for black beans, with a $R^2$ of 0.97 or greater and an RMSE of 0.0308 or less. Conclusions: The Thompson model was the most appropriate prediction drying model for white and black beans. Empirical constants for the Thompson model were developed in accordance with the conditions of drying temperature and relative humidity.