• Journal of Advanced Marine Engineering and Technology
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• v.27 no.2
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• pp.280-288
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• 2003

We need refrigeration system which can maintain the freshness of agricultural products, because of being distance from a tiller to a consumer. Vacuum Pre-cooling system has an advantage in quality maintenance through vapid cooling down by using latent heat of evaporation of stored products. A number or thawing methods in current use have also several disadvantages in thawing time. discoloration mass loss caused by drying, capital costs and running cost. These damages are, it is claimed, either eliminated or improved by the vacuum thawing system. An experimental study on the pre-cooling for the bean sprouts and cabbage, and thawing for hairtail and croaker by the low temperature vacuum system were carried out. The cabbage cooling time with this Pre-cooling vacuum system took about 60 minutes to reach from $23.2^{circ}C to 4.5^{\circ}C$ at 5 mmHg abs. ($6.66\times10^{-4}$ MPa). The croaker thawing time with this low temperature vacuum thawing system took about 170 minutes to reach from $-10.3^{circ}C to -0.8^{\circ}C$ at 20 mmHg abs ($2.67\tiems10^{-3}$MPa). The vacuum Pre-cooling and thawing system have merits compared with present systems in their short intervals to cool down and to thaw without any quality losses.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.305-314
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• 2017

The purpose of this study was to develop the high efficiency of ginseng by using microwave low temperature vacuum drying technology. In red ginseng manufacturing processes, the study results compared the hot-air drying red ginseng dried during 24hours in $60-70^{\circ}C$ and redried during 72hours in $40^{\circ}C$ after the steaming ginseng with the red ginseng dried in microwave low temperature vacuum dryer on condition that 900 watt, 2.45 MHz, 50 mmHg during 5 hours and redried during 2 hours on 750 mmHg after the steaming ginseng about observation of tissue, sensory evaluation and a change of ginsenoside and crude saponin content. As a result, the red ginseng in microwave low temperature vacuum was had high brightness, the surface turned into porosity tissue and added more flavor, decreased bitterness highly on the contrary increased sweetness at the same time that elevated the comprehensive preference. Moreover, In a short time, the content of ginsenosides $Rg_1$ and $Rb_1$ increased about sixfold, eightfold in one time zone but there were no wide difference in content of $Rg_3$ as compared to the hot-air drying red ginseng. Finally, content of crude saponin was increased widely at 10-20 minutes and stayed high crude saponin content consistently. Therefore, this result indicated that the red ginseng in microwave low temperature vacuum increased extraction yields of the ginsenosides and crude saponin through a change of porosity tissue and improved flavor and texture compare with the general hot air dried red ginseng in a short time. According to these results, that provided that could increase the preference about red ginseng.

• 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.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.353-356
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• 1990

The isolation of volatile compounds by vacuum-distillation with freeze-drying was tested 1 with fresh ginseng roots. The roots were frozen at-8$0^{\circ}C$; they were dried at-4$0^{\circ}C$ tinder vacuum(40 tory), for 24 hours; and the ice condensed at the silrface of condenser in the freeze-dryer was thauved at room temperature. The ether extract of the resulting aqueous solution was analyzed by gas chromatography (GC) equipped with a flame ionization detector (FID) or a nitrogen-phosphorils detecto(NPD) and by gas : chromatography/mass spectrometry(GC/MS). More than forty peaks were observed in the CG(FID) profile. and more than ten peaks were observed in the GC(NPD) profile. Among them, thirteen components 1including one aldehyde, four hydrocarbons, two esters, folly alcohols, and two vyrazines were identified: six components the molesuiar ions of which were m/z, 204 were estimated to be a series of azulene compounds; and the other components unidentified were estimated to have molecular weights of lower than 254. Therefore, the freeze-drying technicue is thought to be usefu1 for the isolation of volatile compounds of such low molecufilar weights from vegetables, fruits and biological fluids as well as fresh ginseng roots under the tested conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.460-469
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• 2010

In spite of the global-class aquaculture and fishing technology of our country, the processing technologies are lags behind the other nations relatively. The processed marine products are mainly frozen foods, canned goods, salty food (fermented fish products), fish paste products (boiled fish paste), and we can see that the high-value dehydrated foods by drying are very few. These problems are considered to be caused directly by the lack of drying technologies. This paper is concerned to the experimental results of drying heat transfer characteristics for the green energy type vacuum dryer for the high quality sea foods production.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.9-18
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• 2004

This study was carried out to find the efficient methods for preventing resin exudation from spruce board during high temperature environment service.In the dry-air oven test, in-use temperature related to resin exudation of 110℃ could be obtained by the appropriate kiln drying without any special treatment, and the in-use temperature of the radio-frequency/vacuum (RF/V)-dried boards was about 20℃ higher than that of the conventional kiln-dried boards.In the autoclave test, resin exudation was not found from any board dried in the conventional kiln and in the RF/V kiln after the low pressure steam explosion (SE) treating, while for the control resin exudations were more severe in the autoclave test above 130℃ than in the dry-air oven test. It, therefore, would be suggested that resin exudation during high temperature service condition can be prevented more effectively by super-heated steaming green boards than by high-temperature drying boards with low moisture.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.187-192
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• 2007

The objectives of this study were to examine changes in the color and antioxidant compounds of paprika powder under various conditions, as well as to establish the suitable conditions for drying and storage. Paprika was dried using the following methods: freeze-drying, vacuum drying, far infrared-ray drying, and hot-air drying. Measurements of the moisture content, color pigments, and antioxidant compounds (total carotenoids, capsanthin, ascorbic acid, and total polyphenols) were completed during 120 days of storage at 4 and $30^{\circ}C$. We found that drying methods, storage temperatures, and packaging materials affected the American Spice Trade Association (ASTA) and Hunter color values, as well as the antioxidant content of paprika powder. There was a high correlation (r=0.87, p<0.01) between the ASTA color and the $a^*/b^*$ value. The loss of red color was closely related to the reduction of moisture content (r=0.81, p<0.01) during storage. Drying paprika with a low temperature in the absence of air resulted in better retention of the carotenoids and ascorbic acid. Also, as the retention of the carotenoids and ascorbic acid increased, the stability of the red pigment increased. Freeze-drying was found to be the most suitable drying method for the stability of the antioxidant compounds and red pigment.

• International Journal of Industrial Entomology and Biomaterials
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• v.42 no.1
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• pp.14-20
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• 2021

Mulberry was dried with low temperature vacuum dryer using microwave. The nutritional compositions of microwave-dried mulberry including proximate composition, sugar content, mineral content, total phenolic, flavonoids, and anthocyanin, beta-carotene, vitamin C, and amino acid composition were measured. Sugar contents of mulberry were 42.6 mg/100g (Cheongilppong) and 43.27 mg/100g dw (Gwasang No. 2). The main components of mulberry sugars were fructose and glucose. Mineral analysis showed that K, P, Ca, and Mg were abundant regardless of mulberry cultivars.

• Journal of Life Science
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• v.12 no.5
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• pp.535-543
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• 2002

To investigate the possibility of processing semi-dried jellyfish and to examine its keeping quality, the factors such as moisture content, pH, volatile basic nitrogen (VBN), viable cell counts, color value and texture were analyzed. For processing of the semi-dried product, optimum conditions of drying temperature and drying time were $25^{\circ}C$ and 90min, respectively, under 60 $\pm$ 5% of relative humidity and 2 m/sec of air blast speed. The shelf-life of the products, vacuum-packing method in nylon/polyethylene/linear low density polyethylene (0.015/0.045/0.040 mm) laminated film bag was at least 6 weeks during storage at 4$^{\circ}C$, while that of air packaged one was at least 4 weeks. In case of 2$0^{\circ}C$ storage the shelf-life of the products was at least 3 weeks in both air and vacuum packaged ones.

• Journal of Hydrogen and New Energy
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• v.26 no.6
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• pp.547-553
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• 2015

For commercialization of fuel cell electric vehicles, one of the key objectives is to reduce cost of full stack assembly. Regarding Membrane Electrode Assembly, the major issue is to improve fuel cell activation process in the initial Hydrogen Oxidation Reaction and Oxygen Reduction Reaction. In this research, the VD (Vacuum Drying) process has been developed for improvement of activation process. The VD condition is developed by controlling the temperature and degree of vacuum to remove the remaining solvent of electrode. Consequently, the electrode applied to VD process showed the low characteristics such as 3.5% of remaining solvent content and the improved efficiency such as 15% of activation process speed.