• Title/Summary/Keyword: 냉동효과

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Recent R&D Trend in Magnetic Refrigeration at Room Temperature (실온 자기냉동의 최근 연구개발 동향)

  • Lee, Jong-Suk
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.613-618
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    • 2006
  • The 1st International Conference on Magnetic Refrigeration at Room Temperature was held at Montreux, Switzerland during September 27-30, 2005. The conference was the first of its kind to bring together about 140 scientists and engineers interested in magnetic refrigeration in one place. The magnetocaloric effect was discovered in 1881, however, magnetic refrigeration at room temperature was demonstrated to be viable in 1997 Since then, R&D efforts toward magnetic refrigeration have been on the rise around the world, in both areas of systems and materials. The conference reflected the recent R&D trend in magnetic refrigeration at room temperature, which includes the use of permanent magnet instead of superconductor magnet, switch from reciprocating to rotary magnetic refrigeration system, development of magnetic materials based on transition metal elements besides rare earth materials such as gadolinium(Gd).

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The maintenance of free-living amoebae by cryopreservation (자유생활 아메바의 냉동보관)

  • Seo, Seong-A;Yong, Tae-Sun;Im, Gyeong-Il
    • Parasites, Hosts and Diseases
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    • v.30 no.2
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    • pp.151-153
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    • 1992
  • We have successfully cryopreserved free-living amoebae in order to maintain them feasibly under the conditions in our laboratory. The viability of trophozoites was higher when frozen by slow cooling (overall $0.7^{\circ}C$/min) than by fast cooling (overall $1.3^{\circ}C$/min). Glycerol and dimethylsulfoxide at the final concentration of 7.5% each was used for cryopreservation of free-living amoebae trophosoites. The survival rate was 2∼39% after storage in the liquid nitrogen for 60 days. Gross cultural or morphological changes were not noted in trophozoites thawed from frozen suspensions.

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Reefer Container Monitoring System using Trajectory Information (궤적 정보를 이용한 냉동 컨테이너 모니터링 시스템)

  • Lee, Myung-Jin;Lee, Eung-Jae;Ha, Deok-Cheon;Ryu, Keun-Ho;Baek, Seung-Jae
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.1
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    • pp.23-39
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    • 2005
  • As developing satellite communication, the tracking range of the moving objects which move in local area is expanded to the whole world. However previous logistics management system is able to monitor freight which transporting in local area using mobile communication system. In this paper, we propose the reefer container management system that manages the location information and other related information such as temperature, humidity of container using the satellite system. The proposed system consists of three parts; data collector, satellite communication manager, reefer container information manager. And the proposed system uses the moving object index for managing the trajectory of container and tracing the location of container or vessel that is transporting the container, and supports various services such as reefer container and vessel tracking, container control and container statistics to logistic companies like shipper and forwarding agent. And the system can be increasing the quality of container transportation service to the shipper, and it makes the efficient management of reefer container to the shipping company.

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Effects of Processing Conditions on Nutritional Qualities of Seafood -2. Effects of Cryoprotectants on the Protein Qualities of Pollock Surimi- (해양식량자원의 가공조건별 영양적 품질평가 -2. 명태연육 단백질품질에 미치는 냉동변성방지제의 영향-)

  • RYU Hong-Soo;LEE Keun-Woo;LEE Kang-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.27 no.4
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    • pp.335-343
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    • 1994
  • To determine the optimal level of cryoprotectant on the denaturation of pollock surimi produced in Korea, the relative cryoprotective effects of crystalline sorbitol alone and in combination with sucrose were assessed. Freeze induced protein denaturation was also studied as affected by polyphosphates and maltodextrin during frozen storage at $-25^{\circ}C$ for 16 weeks. Variables evaluated included salt extractable protein, drip loss and in vitro protein quality. The best cryoprotective effect was achieved from sucrose/sorbitol 1:1(w/w) mixture at $8\%$ with $0.2\%$ sodiumpyrophosphate and sodiumtriphosphate(1:1, w/w) in surimi by measurement of salt extractable protein and drip loss. Those cryoprotectants had little effect on surimi protein quality during frozen storage as measured by trypsin inhibitor(TI), protein digestibility and computed protein efficiency ratio(C-PER). Protein digestibility of surimi was not changed significantly by polyphosphate and maltodextrin at various levels(p<0.05), with the exception of 4 or $6\%$ sorbitol and $10\%$ sucrose alone which resulted in a higher digestibility. $8\%$ sorbitol/sucrose (5:3, w/w) treatment without polyphosphates showed the highest cryoprotective effectiveness from digestibility assay.

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Effects of Additives on the Improvement of Frozen Dough Quality (첨가물이 냉동반죽의 품질향상에 미치는 영향)

  • Lee, Young-Chun;Jeong, Hyung-Won;Yoon, Suk-Kwon
    • Korean Journal of Food Science and Technology
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    • v.36 no.2
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    • pp.217-225
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    • 2004
  • This study was carried out to reduce the loss of frozen dough quality during frozen storage. Using response surface method, ascorbic acid 160.4 ppm, L-cysteine 63.1 ppm, and SSL 0.6% were found to be optimum, with xanthan gum 0.3% (formula A) and Ultra tex-3 5% (formula B) added as cryoprotectants. During frozen storage at $-20^{\circ}C$, control rapidly deteriorated after 4 weeks, while formulas A and B showed slight deterioration with immutable quality after 10 weeks.

Effects of Oleoresin Spices on the Quality of Chicken Surimi during Frozen Storage (Oleoresin 향신료의 첨가가 계육 Surimi의 냉동저장중 품질에 미치는 영향)

  • 이성기;민병진;강창기
    • Food Science of Animal Resources
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    • v.21 no.4
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    • pp.292-299
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    • 2001
  • Chicken surimi from mechanically deboned chicken meat was prepared with 0.2% oleoresin spices such as rosemary, thyme, sage, mace, marjoram, and bay. Samples were stored at -18$\^{C}$ for 14 weeks to observe quality change including lipid oxidation, color and textural properties. The pH of surimi decreased from pH 7.44∼7.58 stored at 1 day to pH 7.03∼7.13 stored at 14 weeks. The control surimi showed higher level of pH during storage periods. Color stabiilty of surimi decreased during frozen storage both in control and oleoresin added surimi. Control surimi comparatively maintained higher color stability during frozen storage because of higher L* and a* values, and lower b*. On the contrary, the marjoram addition significantly decreased L* and a* value, and increased b* value compared with other oleoresins. Therefore, the color of surimi seems to be affected original color of oleoresin spice itself. Gel strength showed loser level in oleoresin added surimi than control surimi. Oleoresin spices inhibited lipid oxidation significantly because less thiobarbituric acid-reactive substance(TBARS) were accumulated in oleoresin added surimi than control surimi. Sage was the most effective in minimizing lipid oxidation in frozen surimi as TBARS of sage added surimi stored for 14 weeks maintained only 42% compared with that of control. In conclusion, the 6 kinds of oleoresin in this experiment retarded oxidative rancidity in chicken surimi but there was no beneficial effect on the surface color and gel strength.

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Effect of Gums Added in Making Frozen Dough on the Characteristics of Bread-making (냉동생지 제조시 검류의 첨가가 제빵특성에 미치는 영향)

  • Lee, Jong-Min;Lee, Myung-Ku;Lee, Si-Kyung;Cho, Nam-Ji;Kim, Sang-Moo
    • Korean Journal of Food Science and Technology
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    • v.33 no.2
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    • pp.190-194
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    • 2001
  • This study was carried out to investigate the possibilities of using xanthangum, guargum and ${\kappa}-carrageenan$ as cryoprotectant by examining changes in water content, specific volume, and hardness of bread made from the doughs with gums at $-20^{\circ}C$ freezing chamber for 12 weeks. The specific volume of bread decreased with time. It decreased more sharply in the control. The bread with lowest specific volume had the highest value in the hardness. The bread with ${\kappa}-carrageenan$ showed the lowest value in the hardness. In the water-holding capacity of frozen dough, the bread with ${\kappa}-carrageenan$ had the highest value, and ${\kappa}-carrageenan$ was effective in the protection of the degradation in the quality of the frozen dough during the frozen storage. In the sensory evaluation, texture, color and appearance of the control and the breads with gums did not show the difference for 1 week, but the breads with gums showed the higher score than control in sensory characteristics in the frozen storage for 12 weeks. The bread with ${\kappa}-carrageenan$ showed the highest sensory score during the frozen storage. These results were summarized that ${\kappa}-carrageenan$ was most effective in the protection from the degradation of the quality of frozen dough during the frozen storage.

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Change of Biological Activity of Strawberry by Frozen Storage and Extraction Method (냉동저장 및 추출방법에 의한 딸기의 생리활성 변화)

  • Youn, Sun-Joo;Cho, Jun-Gu;Choi, Ung-Kyu;Kwoen, Dae-Jun
    • Journal of Life Science
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    • v.17 no.12
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    • pp.1734-1738
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    • 2007
  • The biological activities of strawberry were investigated during frozen storage. The concentrations of total phenolic content in strawberry juice and water extract were $2.342{\mu}g/ml\;and\;2.235{\mu}g/ml$, respectively. The total flavonoid content in strawberry juice and water extract were $200.36{\mu}g/ml\;and\;201.07 {\mu}g/ml$. respectively. Antioxidant activities of strawberry juice and water extract were determined. The DPPH of strawberry juice (94.2%) was higher than the water extract of strawberry (93.5%). ABTS of strawberry juice and water extract were 99.9% and 100.0%, respectively. Xanthine oxidase inhibitory activity and SOD-like activity of strawberry of water extracts were higher than those of strawberry juice. The changes in the antioxidant activity of strawberry was insignificant until 6 months of frozen storage. Therefore, it was expected that frozen storage of strawberry was useful preservation expedient for consistent supply of raw materials.

Prophylactic and therapeutic studies on intestinal giant-cystic disease of the Israel carp caused by Thelophanellus kitauei II. Effects of physical and chemical factors on T. kitauei spores in vitro (향어의 장포자충(Thelohanellus kitauei)증의 예방 및 치료에 관한 기초적 연구 II. 물리화학적 요인이 장포자충 포자에 미치는 영향)

  • Lee, Jae-Gu;Kim, Jong-O;Park, Bae-Geun
    • Parasites, Hosts and Diseases
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    • v.28 no.4
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    • pp.241-252
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    • 1990
  • In a basic attempt to develop the prophylactic and therapeutic measures on intestinal giantcystic disease of the Israel carp, C), prinks carpio nudum, the effects of physical and chemical factors on viability or survival of the spores of Thelchcnellus kiteuei were checked in vitro by means of extrusion test on the polar filament. When the fresh spores suspended with 0.45% and 0.9% scdium chloride solution and distilled water were laid at $5^{\circ}C$ and $28^{\circ}C$ for short terms, the extrusion rates increased until the 3rd day, meanwhile when son;e of them were suspended with Tyrode's solution at $-70^{\circ}C$ the rates increased gradually until the 8th day. Viabilities of the spores suspended with 0.9% saline and added antibiotics to the suspension at $5^{\circ}C$ for long terms lasted for 997 days and 1, 256 days (presumed values) at maximum, respectively. The spores suspended with distilled water at $28^{\circ}C$ for long terms survived 152.4 days, but the spores suspended with Tyrode's solution at $-70^{\circ}C$ for long terms showed almost the same viable pattern as early freezing stages up to 780 days. The spores suspended with Tyrode's solution, frozen at $-70^{\circ}C$ and thawed at $5^{\circ}C$, showed the highest rate of extrusion of the polar filament. In the case of frozen spores, the extrusion rates during heating tend to become higher in accordance with the increase of frozen period, and the critical points of 180 day-frozen spores to be killed were generally 78.5 hr. at $60^{\circ}C$, 23.4 hr. at $70^{\circ}C$, 189.1 min. at $80^{\circ}C$ or 10.5 min. at $90^{\circ}C$. The longer the spores were frozen, the more time was needed for the death of spores after thawing; 20 days-17.4 days, 100 days-33.2 days, and 400 days-37.8 days. The longer the spores were frozen, the more time was needed for the death of spores at a conventional when they were dried air drying condition, 540 days-23.5 days, 160 days-21.0 days, and 20 days-14.4 days. On the other hand, the longer the spores were frozen, the more spores were dead rapidly when they were irradiated with 10W UV-ray; 100 days-26.0 hr, 300 days-21.9 hr, and 540 days-13.9 hr. The time needed for killing 200 days-frozen spores by various disinfectants at 1, 000 ppd was 5.2 min. by calcium oxide, 10.4 min. by potassium permanganate, 27.8 min. by malachite green and 14.3 hr. by formalin. Transient inhibitory effects of the extrusion of the polar filament were observed by various antiprotozoal and antifungal agents in the descending order of ketoconazole. metronidasole and dapsone. The above results presume that full drying, followed by spraying CaO and maintaining sunny condition for a few days on the concrete bottoms of knish farm may be an effective method for the prevention of intestinal giant.cystic disease.

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