• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.509-514
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• 2000

A numerical study has been performed to design duct parameters in the freezer of a domestic refrigerator. The visualization results of FDM analysis using the standard k-$\varepsilon$ model with inlet boundary conditions modelled in this paper show good agreements with the experimental ones in prediction overall flow characteristics. Dominant vortex flows are found in the left upper and right lower corners, while there exists large turbulent kinetic energy around the fan and right upper side of the fan. It, in turn, has effects on the performance and noise. It is recommended to locate the outlet far away from the fan in order to reduce the noise level.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.743-748
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• 2011

The performance of HFO-1234yf as a substitute for R-134a was evaluated in a household freezer/refrigerator. A series of tests such as 'refrigerant charging test, pull-down test, cooling speed test, and energy consumption test were carried out under the AHAM (Association of Home Appliance Manufacturers) standard. The results of a drop-in test were compared with those of a test conducted using R-134a. A test under a severe ambient air condition ($43^{\circ}C$) was also conducted. The result shows that the refrigeration cycle performance of HFO-1234yf is as good as that of R-134a ; however, the diameter of capillary tube should be increased in order to improve its performance in the cooling speed test.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.330-335
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• 2014

Purpose: This study was conducted for enhancing the performance of a conventional quick freezer by introducing the supercooling state, using a low-temperature coolant. Methods: In the present investigation, the supercooling process was executed prior to quick freezing for reducing the time by which the temperature passes the zone of maximum ice crystal formation. Every food has different nucleation points and hence, we used silicone oil as the coolant for supercooling for easy modification of temperature. Additionally, for quick freezing, we used liquid nitrogen spray. Results: Using the heat exchanger-type precooler with silicone oil, the temperature of the chamber was easily changed for enabling supercooling. Particularly, the results of the freezing test with garlic indicated that this system improved the hardness of garlic after it was thawed, compared to the conventional freezing method. Conclusions: Before quick freezing, if the food item is subjected to the supercooling state, the time from nucleation to the temperature reaching the frozen state ($-5^{\circ}C$, which is the maximum ice crystal formation zone) will be shorter than that incurred using quick freezing alone. The combination of the heat exchanger-type supercooler and liquid nitrogen sprayer is expected to serve as a promising technology for improving the physicochemical qualities of frozen foods.

• Journal of Pharmaceutical Investigation
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• v.30 no.1
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• pp.21-26
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• 2000

Bioavailability of ipriflavone (3-phenyl-7-isopropoxy-4H-I-benzopyran-4-one, IP), an antiosteoporotic drug with poor water-solubility, was studied for various types of pharmaceutical preparation in SD rats. The IP preparation types included (1) intact IP, (2) freezer milled IP (FIP), (3) freezer milled IP physically mixed with freezer milled poly-N-vinylpyrrolidone (PVP) (FIP+FPVP) and (4) spray-dried IP with PVP (SIP). Upon oral administration, SIP showed significantly higher absorption and elimination half-lives and the lag time $(t_{lag})$ than those of FIP+FPVP (approximately 2-fold). These results may be due to a sustained releasing effect of IP in the gastrointestinal tract by spray-drying with PVP. The $C_{max}$ of SIP was about 2 and 10 times higher than those of FIP+FPVP and FIP, respectively. The AUC of SIP was about 6 times higher than that of FIP+FPVP and 60 times that of FIP. Scanning electron microscopy (SEM) showed that SIP consisted of the finest particle size and minimal aggregation than other IP preparations. It is concluded that the IP formula prepared by the spray-drying method with PVP is the most effective approach to the improvement of bioavailability of IP.

• The Korean Journal of Mycology
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• v.42 no.2
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• pp.97-103
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• 2014

A total of 7039 strains of filamentous fungi are preserved in Korean Agricultural Culture Collection (KACC). The 4065 strains (58%) of them, which produce many spores in cultivation on proper media, are preserved with freeze-drying method. They are also preserved with liquid nitrogen and deep-freezer storage in order to minimize loss by death. Aspergillus, Penicillium, Lichtheimia, Mucor, Rhizopus, etc. which are common in surrounding environments, are included in this category. The others which do not produce spores, or produce few spores in vitro, are preserved with liquid nitrogen, deep-freezer and mineral oil storage. Phytophthora, Pythium, Cercospora, Septoria, Rhizoctonia, etc. are included in this category. The authors also introduced various fungal preservation methods and provided detailed preservation procedures that are used in KACC.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.19-24
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• 2015

The economic efficiency for fishery products can be related to their freshness and the quality. In order to freshly storage the product, freezing equipment system is necessary for fishing vessels. For this purpose, the horizontal plate freezer (HPF) is mostly used. In this research, our major objective is to improve the freezing performance of the HPF. Therefore, it is important to analyse the relationship between the shape of channels and the cooling temperature of the HPF. In order to save calculation time while checking the trend analysis between shape and performance, we used scaled models, and evaluate the cooling temperature of full scale model based on trend analysis results. The produced HPF in domestic was used, and the same operating conditions are considered. Based on this paper, the future research will be a comparison and verification through the experiments.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.15 no.2
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• pp.57-72
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• 2004

This study is carried out to investigate the effect of any periods in the freezer and the product of value, moisture content, baking loss, specific volume loaf in manufncturing process thereof. The moisture content of the croissant slightly decreased as the periods passed in the freezer. And as passed periods frozen croissant dough dried naturally by the freezer fan. 1. As frozen periods passed croissant dough decreased moisture content and loaf volume. The volume is relation to the molsture content and croissant dough' gluten. Yeast is active but croissant dough is dried so pastry margarine's moisture vaporized little by little. 2. 1 day frozen bench time provided maximum specific loaf volume while croissant shape was unsettled, moisture content was highest. At the same dough croissant hardness had very sofi crust. 3. 1week and 2weets frozen dough had specific loaf volume and hardness with proper crust color. As the proper bench time provided best shape of croissant, color. 4. 4weeks and 8weeks frozen dough had over-al] value of croissant accelerating older product. As the same result, over Sweets frozen periods product were not available for sale and serving to customers. 5. By the sensory evaluation tests, over-all croissant as 1 week, 2weeks were significantly higher quality those than 6. 1day, 4weeks and 8weeks. Textural properties of croissant over 4weeks frozen periods so hard for every panel. According to the study, not croissant dough but also any other frozen dough(ex.Danish, brioche etc.)have to need proper bench time and 1week or 2weeks circulation making method have to given encouragement to practical pastry industry. Add to this study using only for frozen dough yeast instead of using fresh and instant

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1589-1595
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• 1999

Reverse osmosis(RO) and rotary evaporation, freezer drying and spray drying as concentration and dehydration methods were, respectively, employed to investigate their effect on the flavor quality of ginger powder. Rotary evaporation and spray drying methods were more effective to restrict the browning of ginger powder than RO and freezer drying methods. Concentration methods had no effect on the free amino acids and free sugar contents of ginger powder, but freezer drying resulted in the less quality loss than spray drying. And the powder prepared from enzymatically hydrolyzed extract contained less crude protein, crude ash, browning and the changes in free amino acids, but had more the crude fat, solubility and free sugars than that from ginger extract obtained by filter press. Sensory results indicated that quality of ginger powder prepared by RO concentration and freeze drying of enzymatically hydrolyzed extract was as good as that without enzyme hydrolysis

• Journal of the Korean Society of Food Culture
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• v.34 no.3
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• pp.343-352
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• 2019

The aim of this study was to optimize the best recipe to make acorn bread containing milk as a functional food. The color value, textural, and sensory properties of the acorn bread added with 10~40% ratio of milk were measured to develop the best recipe. As a result, the L-value of color increased with the amount of milk added, but the a- and b-values decreased. As the textural measurement, the hardness increased with increasing milk added. Cohesiveness and springiness decreased, but the gumminess and brittleness increased with the addition of 20% milk, and decreased with further addition. The sensory evaluation revealed color, taste, and overall acceptances to have high scores at 20% addition of milk. Softness and chewiness were good at 10% addition. During the storage periods at room temperature, the L- and b-values increased with the addition of milk, whereas a-value decreased. In freezer storage, the L-value increased with milk content added, but the a- and b-values decreased during the storage periods. The textural properties increased during the storage at room temperature. The addition of milk decreased the cohesiveness and springiness, but the gumminess and brittleness increased significantly after one day storage. In freezer storage, all textural properties increased significantly during the storage periods, but the hardness decreased after two days storage. With the increasing amount of milk added increased the cohesiveness, springiness, and the gumminess except for four days, but decreased hardness and brittleness after two days storage. Therefore the addition of milk in acorn bread improved the textural properties significantly.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.94-94
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• 2004