• 연구논문집
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• s.22
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• pp.141-150
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• 1992

A basic study on the batch type freeze dryer has been carried out. The operating principles, merits and demerits of the freeze dryer were described. And the kinds of major components and their roles were also invesigated. As a fundamental study, using the Differential Scanning Calorimeter(DSC), the determination of unfrozen water in the specimens and invesigation of effects of cooling rate on the freeze drying were performed. To provide a guidline of basic design for a freeze dryer, a parametric study about the drying conditions was carried out.

• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.21-26
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• 2015

A wireless sensor network (WSN) is designed and implemented for a freeze dryer. Freeze-drying technology is widely used in the fields of pharmacy and biotechnology as well as the food and agriculture industries. Taking into account the demand for high-resolution pressure and temperature measurements in a freeze dryer, the proposed WSN has a significant advantage of creating a monitoring environment in a freeze dryer. The proposed WSN uses a ZigBee/IEEE 802.15.4 network with an altimeter module that contains a high-resolution pressure and temperature sensor with a serial digital data interface. The ZigBee network is suitable for low-energy and low-data-rate applications in the field of wireless communication. The altimeter module is capable of sensing pressure in the range of 7.5-975 Torr (10-1300 mbar) and temperature in the range of $-40^{\circ}C$ to $125^{\circ}C$ with a DC power consumption of $3{\mu}W$. The implemented WSN is installed in a commercial laboratory freeze dryer in order to demonstrate its functionality and efficiency. A comparison with the temperature profile measured by a thermocouple installed in the freeze dryer reveals that the resolution of the temperature profile measured by WSN is superior to that measured by the thermocouple.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.350-356
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• 1988

A pilot plant scale freeze dryer was designed and manufactured and its performance was tested. Freezing capacity of water vapor in the developed freeze dryer was 8㎏/batch and heating and defrosting methods were conduction and hot gas types, respectively. And exhausting time of vacuum pump was 7-8 minutes and temperature of cold trap was kept below $-50^{\circ}C$. In the freeze drying of fruits and vegetables, its optimum and maximum drying capacities were 2 and 4㎏/batch, respectively. Performance of the new freeze dryer was compared quite well with a foreign made freeze dryer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.60-65
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• 2008

Chemical properties of barley leaf were investigated using different drying methods. Moisture contents of barley leaf were 75.22%, 7.54%, 2.57%, 6.74% and 8.91% for samples dried using raw, hot-air dryer, freeze dryer, shade dryer, vacuum freeze dryer and microwave dryer, respectively. Mineral contents were high Ca, Mg, Na, P, and K in barley leaf regardless of drying methods. Organic acid contents were oxalic acid, acetic acid, citric acid and fumaric acid with no differences between drying methods. Contents of vitamin C were 142.56 mg%, 629.23 mg%, 598.48 mg%, 657.62 mg% and 724.34 mg% for samples using raw, hot-air dryer, freeze dryer, shade dryer, vacuum freeze dryer and microwave dryer, respectively. Chlorophyll contents of barley leaf dried by hot-air dryer and shade dryer were higher than in that of freeze dryer and microwaves dryer. b-values were lower in freeze dryer than in that of other dried methods.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1323-1328
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• 2004

This paper shows the study on the design of the spray-freeze dryer for the production of the pulmonary inhalation powders. Powder production and handling has been an integral part of pharmaceutical processing because of the wide use of oral dosage forms. There are a few commonly used powder preparation methods including mechanical milling, precipitaion, spray drying, freeze drying, and so on. In general, methods available for preparing inhalation powders are limited due to certain inhalation powder's sensitive nature to the processing environments. This is particularly true for preparing dry powder aerosols where the aerodynamic particle size$(<5{\mu}m)$ and the size distribution are pivotal. Supercritical fluid antisolvent and spray freeze drying have recently emerged as promising techniques for producing powders for use in microcapsulation. However, the aerosol applications of these powders are yet to be explored. The purpose of this study is to test the feasibility of using spray freeze-dried pulmonary inhalation powders for aerosolization.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.1-6
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• 2004

This paper shows the study on the design and another applications of the spray-freeze dryer for the production of valuable material powders. Powder production and handling has been an integral part of material extracting processing and pharmaceutical processing because of the wide use of oral dosage forms. There are a few commonly used powder preparation methods including mechanical milling, precipitaion, spray drying, freeze drying, and so on. In general, methods available for preparing inhalation powders are limited due to certain inhalation powder's sensitive nature to the processing environments. This is particularly true for preparing dry powder aerosols where the aerodynamic particle size($<5{\mu}m$) and the size distribution are pivotal. Supercritical fluid antisolvent and spray freeze drying have recently emerged as promising techniques for producing powders for use in microcapsulation. However, the aerosol applications of these powders are yet to be explored. The purpose of this study is to test the feasibility of using spray freeze-dried valuable material powders for aerosolization.

• Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.19-31
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• 2021

Seaweeds are a potential source of minerals, essential amino acids, fatty acids, proteins, and various bioactive compounds such as antioxidants. The higher water content of seaweeds reduces the shelf life and this requires the appropriate drying method. The drying conditions play a major role in the conservation of nutrient composition in dried seaweeds. In recent years, the seaweed industry has used many different drying methods with advantages and limitations. Hybrid hot-water Goodle dryer (HHGD) which is a special dryer mixed with hot-water and a Korean traditional heating system (Goodlejang) might be a solution to avoid these limitations. The present study evaluated the effect of drying conditions in HHGD on nutrient composition and bioactivities of brown seaweeds. Moreover, freeze-dryer (FD) and HHGD were employed in this study to compare the dried outputs obtained from four brown seaweed species. The present study aims to evaluate the effect of the hybrid hot-water Goodle drying method (HHGDM) on the nutritional composition and antioxidant activity of dried seaweeds. AOAC standard methods were used to analyze the proximate composition of dried samples and their 70% ethanol extract. The intracellular and extracellular antioxidant activities were evaluated using Vero cells and electron spin resonance (ESR) spectrometer respectively. High performance liquid chromatography, apoptotic body formation, and in-vivo experiments were used for further confirmation of the quality of dried output. The proximate composition results obtained from drying in HHGD and FD did not exhibit any significant difference. Moreover, the seaweed extracts from the dried seaweeds by HHGD and FD dryings were also not different and both significantly down-regulated in-vivo and in-vitro oxidative stress. Furthermore, the high performance liquid chromatography results revealed that the two dryers did not make the major peaks different in the chromatograms. Freeze-drying method (FDM) provides elevated quality for dried output, but there are limitations such as high cost and low capacity. The results from a novel HHGD did not provide any significant difference with the results in FD and expressed a potential to avoid the limitations in FD. Overall, these findings solidified the applicability of HHGD over FD.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.342-347
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• 2007

Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%, and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (p>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.05) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (p<0.05).

• Journal of Life Science
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• v.18 no.9
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• pp.1271-1277
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• 2008

We investigated to determine the inhibitory effects of solvent extracts from dried onion on growth of cancer cell lines (HT-1080 human fibrosarcoma and HT-29 human colon cancer cells) and $H_{2}O_{2}$-induced oxidative stress. Two different drying methods, low temperature vacuum dryer and freeze dryer, were employed to dry onion. Inhibitory effects of acetone with methylene chloride (A+M) and methanol (MeOH) extracts from onion by two drying methods on the growth of HT-1080 and HT-29 cancer cells increased in a dose dependent manner (p<0.05) and the higher inhibitory effect was shown in onion extracts dried by low temperature vacuum dryer. The treatments of hexane, 85% aq. methanol, butanol and water fractions significantly inhibited the growth of both cancer cells (p<0.05) and onion fractions dried by freeze dryer showed a higher inhibitory effect compared with those dried by low temperature vacuum dryer. In order to determine a protective effect on H2O2-induced oxidative stress, DCHF-DA (dichlorodihydrofluorescin diacetate) assay was conducted. All fractions including crude extracts of dried onion appeared to significantly reduce the levels of intracellular reactive oxygen species (ROS) (p<0.05). Higher antioxidant effect was observed in onions dried by the low temperature vacuum dryer method. These results indicate that the low temperature vacuum dryer is useful to dry and produce onion powder.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.2088-2098
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• 1993

A mathematical model of freeze drying by sublimation was suggested and used to estimate the drying time. Under the various conditions, the drying time of pure water and carrot was numerically calculated for the suggested model. Optimal policies of freeze drying were investigated experimentally in a laboratory freeze dryer. It was found that the shortest drying times could be obtained when the chamber pressure and condenser temperature were kept at their lowest values and the best method of heat transfer for sublimation was the conduction involving radiation. The sublimation drying period was finished when the bottom temperature of material could be reached at near $0^{\circ}C$ from frozen temperature.