• Journal of Biosystems Engineering
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• v.13 no.4
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• pp.38-45
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• 1988

The freeze drying of garlic juice was carried out in a vacuum freeze dryer, laboratory size, by backface heating. The factors which influence the rate of freeze drying, the pressure of drying chamber, the plate temperature, the concentration and the thickness of a sample, were discussed in this study. The drying rate was in proportion to the drying chamber pressure and when the pressure was at 1.5 torr, the foaming occured on the surface of materials, so this condition was not suitable for freeze drying. As the temperature of plate increased, drying rate increased, but when the temperature was $20^{\circ}C$, it was impossible to accomplish freeze drying because the foaming and the dispersion occured in a sample. The higher the concentration of a sample was, the lower drying rate was.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.165-173
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• 2020

Fish roe is among the most valuable food resources produced by fisheries. Raw fish roe requires processing for conversion into hygienic, marketable, and consumer-acceptable forms. In this study, to investigate the food compositional characteristics of various types of fish roe, we applied vacuum freeze-drying to prepare fish roe concentrates (FRCs) from roe of Alaska pollack Theragra chlcogramma, bastard halibut Paralichythys olivaceus, and skipjack tuna Katsuwonus pelamis. The FRC yield ranged from 22.7 to 26.7 g/100 g roe. The major constituents of FRCs were protein (65.4-79.6%), moisture (2.8-6.2%), lipids (8.5-18.3%), and ash (4.8-7.2%). Potassium, sulfur, sodium, and phosphorus were the major mineral elements of FRCs, and the major amino acids were aspartic acid (9.0-10.4 g/100 g protein), glutamic acid (13.2-14.5 g/100 g protein), lysine (8.4-8.6 g/100 g protein), and leucine (8.3-9.7 g/100 g protein). Vacuum freeze-dried FRCs differed among fish species in terms of amino acid composition and electrophoresis protein band distribution. Therefore, FRCs are an excellent source of protein nutrition and an appropriate protein fortification material in human foods or animal feed.

• Journal of Conservation Science
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• v.37 no.5
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• pp.579-589
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• 2021

Five waterlogged wood artefacts were excavated from Suyeong-ri site in Hwaseong, South Korea. The aim of the present study was to identify the species and estimate the date of manufacture and the manufacturing method of these artefacts. The study also aimed to conserve the original shapes of waterlogged wood artefacts by using the vacuum freeze drying method. The two large waterlogged woods were identified as Ulmus spp. and Morus spp., whereas one of the three small waterlogged woods was identified as Abies spp. and the other two as hard pine. Radiocarbon dating using wiggle match dated the manufacturing of these wooden artefacts between BCE 8520-8490 or BCE 8470-8290 in the Neolithic age, and a similar period was also confirmed for seed excavated from a place close to the location where the waterlogged wood artefacts were excavated. The surface of waterlogged wood artefacts had several traces of manufacturing processes - traces of tearing and chopping - were observed. Based on these observations, it was confirmed that stone adz was used to make these wooden artefacts. Thereafter, the waterlogged wood samples were conserved by immersing them into PEG#4,000 of concentration in water from 10% to 40% at room temperature(15~25℃) and subjecting them to vacuum freeze drying. However, the internal moisture was not completely removed in some thick parts of waterlogged woods by applying the general schedule such as raising the shelf temperature as the surface temperature rises. Therefore, additional study is required using the schedule-method for vacuum freeze drying of large waterlogged wood.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.153-163
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• 2021

This study was conducted to examine the effects of starch noodles (dangmyeon; SNs) with different starch sources and porcine intestines (PIs) with different pH on the rehydration stability of Korean blood sausage (sundae). Mungbean SN3 and PI3 (pH 9.18) showed significantly higher values of 80.69%-91.67% and 79.66%-80.98%, respectively, regardless of the drying methods (hot air, vacuum and freeze drying) (p<0.05). A number of larger pores were observed only in the cross-section of the freeze dried SN and PI through SEM. SN2 (potato starch) and PI3 (pH 9.18) showed lower expansion (⁎ΔL 6.90 mm) and higher expansion ratio (⁎ΔL 26.29 mm), respectively, after rehydration of freeze dried sample (p<0.05). From the application of SN2 (potato starch) and PI (0.5%-2.0% Na-pyrophosphate) to freeze dried sundae manufacturing, higher rehydration stability of more than 91.5% was obtained. These results suggested that potato SN and treatment of PI with Na-pyrophosphate is useful for desirable rehydration stability of freeze dried sundae.

• Conservation Science in Museum
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• v.7
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• pp.43-51
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• 2006

From the low swamp remains in Sinchang-dong, Gwangju, a number of wooden lacquerware along with various wooden artifacts were excavated. These excavated lacquerware have deteriorated and weak wooden parts and the lacquer layer come off from the wooden parts; they are very likely to peel off and crack. Therefore, we impregnated the lacquerware in PEG#4000 40% solution that was effective for vacuum freeze drying and finished freeze-drying below 0°…. We compared the weight of wood and lacquerware right after the freeze-drying with the weight after leaving them in a airtight space with 60% RH (relative humidity). The comparison results showed no change in weight; thereby we confirmed controlling the finishing temperature during freeze-drying could control the moisture in wood after drying and it could stabilize wood against the change in moisture in the atmosphere. according to the analysis of the lacquer fragment, the base layer was pasted on the wooden surface with mixed black pigment and the upper layer was pasted three or four times with the mixture of lacquer and black pigment; or it was pasted without the black base coating.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.10
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• pp.743-748
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• 2013

The purposes of this study are to prepare Hanji fiber-filter sheets using replacement liquid in water-swollen fiber with non-polar solvent such as ethanol, methanol and pentane. The experiments were studied on the selection of optimal non-polar solvent and the optimal drying method for wetted fiber and then were to know physicochemical characteristics of prepared Hanji fiber-filter sheet. The Ethanol as liquid changer in water-swollen fiber was excellent solvent and the optimal drying method for them was freeze drying served with vacuum pump. The bulk density and porosity of prepared fiber sheet from freeze dryer were 0.11-0.13 g/mL, half of natural dried fiber sheet, and 90%, respectively. The results of SEM observation for the fiber sheet prepared with natural drying or heating drying were shown very close structure of fiber wall in dry state. However, the freeze drying sheet were shown the open structure. So, the head loss of freeze drying sheet was very lower than natural drying and heating drying sheets. From the results of BTEX removal experiments, the sheets dried at water wetted condition was shown more higher efficiency than the fiber sheets dried at solvent wetted condition.

• Conservation Science in Museum
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• v.11
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• pp.49-52
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• 2010

A wooden Comb excavated at Shinchang-dong wetland site was treated with cetylalcohol as a reinforcing agent. The conservation process was done by freeze drying the wooden artifact after substituting it with no.3 butyl alcohol and impregnating with 40wt% cetylalcohol solution. Consequently there was no noticeable surface damage. Also it showed 54% of remaining weight and a shrinkage of length 3.3%, width 2.1% and thickness 3.1%. Therefore using cetylalcohol for conservation of waterlogged archeological wood was effective dimensional stability and remaining weight.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.32-36
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• 2009

The physical properties of freeze-dried Aloe vera gel powders were examined according to the influence of the concentration degrees of the gel solutions as raw materials during freeze-drying. As a pre-treatment prior to freeze-drying, the gel solutions were vacuum-concentrated at three concentration levels (g water/g solids): high (H), 76; medium (M), 119; and low (L), 159. The water contents of the three powder samples were almost the same. For their viscosity measurements, non-Newtonian fluid behavior with shear thinning was observed in samples H and M, whereas Newtonian liquid behavior was found in sample L. In electrical conductivity measurements, sample H showed the highest conductivity upon dissolving the powder in water. For their water sorption isotherms, sample H was analyzed to have the least amount of bound water. Finally, it was determined that the degree of concentration caused only slight differences in the physical properties of freeze-dried Aloe gel powders.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.153-160
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• 1999

Storage stability of boiled and freeze dried loach and antioxidative effect of Zanthoxylum schinifolium were studied to confirm the possibility in development of instant choo o tang(Korean traditional loach soup). Packaging and storage temperature did not cause a measurable change in in vitro protein digestibility and trypsin indigestible substrate within 45 days of storage but remarkable quality changes were occurred in all samples stored after 60 days. Vacuum packaging and low temperature storage(4 oC) had some effect in retarding protein quality deterioration due to delaying polyunsaturated fatty acid oxidation. Maximum peroxide value and TBA value were reached in 15 days, and there were a slow(TBA value) and rapid reduction(POV) after peaks were reached. In contrast, increasing brown pigment development and fluorescence intensity continued until 90 days of storage. Treatment of ethanolic extracts from Zanthoxylum schinifolium prior to freeze drying could protect against lipid oxidation of freeze dried loach products.