• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.516-519
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• 2000

Generally pancreas consist of lipid, water and protein, digestion enzyme complex (pro-tease, lipase, amylase). The sample used in this work was frozen dry and treated by a semi-batch flow type. In order to develop a supercritical fluid extraction process to rem-ove lipid from the pancreas, experiments were conducted at various operating conditions(pressure range $1500{\sim}2800psi$, temperature range $25{\sim}40^{cdot}C$, particle size$(0.25{\sim}1.0mm$, flow rate $20{\sim}80m{\ell}/min)$. Also cholesterol in the pancreas was removed. The highest extraction efficiency was 2500psi, $35^{\cdot}C$, 0.25mm of pancreas size. The enzyme activity of the pancreas produced from this work showed high value compared with imported pancreas.

• Clean Technology
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• v.10 no.3
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• pp.139-148
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• 2004

The recovery of stainless steel fiber by removing cutting oil from grinding swarf, which is classified as specified wastes, was investigated. Swarf loaded with grinding oil was regenerated by supercritical carbon dioxide. And, the effects of temperature(313.15K-323.15K), pressure(10MPa-30MPa) on regeneration efficiency were studied. Regeneration effiency was increased as the pressure was increased. Also, at the same pressure, the experiments at higher temperature were more efficient for regeneration. The experiment results was predicted by applying a one-parameter mathematical model assuming linear desorption kinetics. The predicted value showed good agreement with experimental data.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.750-755
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• 1996

Citrus juice was treated with supercritical carbon dioxide $(SC-CO_{2})$ and the effect of temperature and pressure on quality of citrus juice was determined. Pectinesterase (PE) was inactivated by $(SC-CO_{2})$ below temperatures necessary for thermal inactivation. There was no significant change in the pH, Brix and total acidity of citrus juice before and after $(SC-CO_{2})$ treatment, but brightness was improved. More ascorbic acid was retained during $(SC-CO_{2})$ treatment of citrus juice than thermal treatment $(93^{\circ}C/0.66\;min)$.During storage of supercritically treated citrus juice at $4^{\circ}C$, activity of PE was reversible. Sensory evaluation showed that color, flavor, taste and overall acceptance of $(SC-CO_{2})$ treated juice were not significantly different from untreated juice. This method offers potentially beneficial processing avenues for citrus juice and other juices, especially in the area of minimally processed products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1847-1855
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• 2015

Supercritical carbon dioxide ($SC-CO_2$) treatment has been becoming an important method for substituting the use of organic solvents for samples extraction prior to analysis due to its low toxicity, ease of handling, low cost of disposal etc. Freeze-dried bovine liver was treated with $SC-CO_2$ under different pressures (200, 300, and 450 bar) in order to investigate effects on physicochemical properties and reduction of microbial load. The yield of lipid extraction from bovine liver by $SC-CO_2$ treatment increased with increasing pressure, with values of 84, 86, and 90% in response to 200, 300, and 450 bar, respectively. Results of high performance liquid chromatography analysis showed that vitamin A and coenzyme $Q_{10}$ ($CoQ_{10}$), which is soluble in lipid, were almost removed from bovine liver by $SC-CO_2$ treatment. Saturated fatty acids ratio of bovine liver decreased with increasing pressure, whereas polyunsaturated fatty acids increased with increasing pressure. Total content of amino acids in bovine liver treated by $SC-CO_2$ was less than that of the control sample without treatment. The number of aerobic bacteria in bovine liver, which was stored at $5^{\circ}C$ for 5 days and freeze-dried, decreased from 6.2 to 4.2 log CFU/g by $SC-CO_2$ treatment at 100 bar for 3 h. Interestingly, coliform bacteria were not found in the bovine liver sample by $SC-CO_2$ at 100 bar for 3 h under all storage conditions. This indicates that $SC-CO_2$ treatment can effectively reduce coliform bacteria in the food matrix even at low moisture. In conclusion, freeze-dried bovine liver by proper $SC-CO_2$ treatment may be used as a potential high protein source, with increasing microbial safety and stability of lipid oxidation.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.373-374
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• 2000

최근 대기중 이산화탄소함량의 증가는 지구온난화의 관점에서 상당한 주목을 받고 있으며 이산화탄소의 흡수저장 능력을 가진 산림내 탄소저장능력에 대한 관심을 증가하고있다(Vitousek, 1991; Alban 과 Perala, 1992). 주로 유기물로 존재하는 산림생태계내 유기탄소는 지구탄소순환에 크게 기여할 뿐만 아니라 토양 이화학적 특성과 밀접한 관련을 가지는 것으로 알려져 있다(Alban 과 Pelara 1992). 본 연구는 경기도 광릉에 위치한 밀도와 지위가 다른 31년생의 성숙한 리기다소나무임분을 대상으로 탄소저장량과 년 탄소증가량이 어느 정도 되는지를 알아보기 위해서 실시하였다.(중략)

• Korean Journal of Materials Research
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• v.6 no.3
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• pp.324-332
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• 1996

DLC 박막을 RF 플라즈마 화학증착법(PECVD)을 이용하여 CH4와 CO2기체로부터 합성하였다. 증착압력, CH4와 CO2가스의 조성비, 바이어스 전압(-VB) 등의 증착조건 변화에 따른 증착속도는 증착층의 두께를 알파스텝으로 측정하여 결정하였으며, 박막의 구조 변화에 따른 증착속도는 증착층의 두께를 알파스텝으로 측정하여 결정하였으며, 박막의 구조 변화는 FTIR 분광분석을 이용하여 분석을 행하였다. 이 연구로부터 얻은 실험 결과는 다음과 같다: 1) 증착속도는 증착압력 및 바이어스 전압의 증가에 따라 증가한다. 2)바이어스 전압 300V이상에서, CO2량 증가는 순증착속도를 증가 시킨다. 3) 순수한 CH4가스를 사용할 경우에는 바이어스전압(-VB)이 증가함에 따라 박막내 수소의 함량과 sp3/sp2비는 감소하는 경향을 나타낸다. 4)증착압력이 증가함에 따라 박막내 수소함량은 증가하며, sp3/sp2비는 감소한다. 5)50mTorr의 증착압력에 증착시, CH4-+Co2 혼합가스에서 이산화탄소의 부피분율에 따라서는 박막내 수소함량은 감소하며, sp3/sp2비는 증가한다.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.169-174
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• 1984

The changes of the content of organic acids, carbon dioxide, alcohols and carbonyl compounds of the various Kimchis which were made of cabbage with green onion, garlic, ginger or red pepper and fermented at $12^{\circ}C-16^{\circ}C$ were investigated. Nonvolatile organic acids identified were lactic, succinic, fumaric and malic acid. Volatile organic acids identified were acetic, formic, propionic, butyric, valeric, n-caproic and n-heptanoic acid. Carbonyl compounds identified were acetaldehyde and acetone. The content of lactic acid was increased with fermentation, and higher in Kimchis containing red pepper, garlic and green onion. The content of acetic acid was increased with fermentation, especially in Kimchi containing garlic. The content of carbon dioxide was higher in Kimchi containing garlic. Alcohols identified in all Kimchis was only ethanol. Carbonyl compounds had no direct effect on off-flavor of Kimchi.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.69-75
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• 2005

The storability of chicon was compared by packing it with PE box, wrap, LDPE (low density polyethylene) film that was 25 and 50um thickness, respectively and storing at 1 and $10^{\circ}C$ under light and dark conditions. The visual quality depending on dehydration was deteriorated at more than $2\%$ weight loss during storage. In packing treatments, chicon packed with PE box lost fresh weight to $3\%\;at\;10^{\circ}C\;and\;2\%\;at\;1^{\circ}C$, while non- penetrated film treatment, wrap, 25 and 50um thickness LDPE film, showed less than $1\%$ weight loss. The carbon dioxide concentration in package was $3\~4\%\;in\;50{\mu}m$ LDPE film at $1^{\circ}C\; and\;25um$ LDPE film at $10^{\circ}C$. The ethylene concentration in 50um LDPE film at $1^{\circ}C\;and\;25{\mu}m$ LDPE film at $10^{\circ}C$ was approximately 0.3 ppm and 0.5 ppm, respectively. Chiton stored in dark condition didn't turn to green, but it fumed green only in 3 days at $10^{\circ}C$ and in 6 days at $1^{\circ}C$ under light condition. The greening of chicon was less, the packing materials was thicker. The chlorophyll content represented the degree of greening showed less at $1^{\circ}C$ then at $10^{\circ}C$. The coefficient of correlation(r) between chlorophyll content and carbon dioxide concentration in package was 0.926 at $1^{\circ}C$ and 0.997 at $10^{\circ}C$. The visual quality except greening of packed chicon was maintained at $1^{\circ}C$ better than $10^{\circ}C$, and it was shown highest grade packed with $50{\mu}m$ LDPE film at $1^{\circ}C$ and packed with 25um LDPE film at $10^{\circ}C$. The vitamin C content in packed chicon was kept higher at $1^{\circ}C$ on storage temperatures, and 25um and 50um LDPE film on packing materials. According to these results, it can be proper condition for storage and marketing of chicon that 50um LDPE film at $1^{\circ}C$ and 25um LDPE film at $10^{\circ}C$. And dark condition is necessary to store chicon because it should turn green under tiny light condition.

• Membrane Journal
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• v.14 no.3
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• pp.250-257
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• 2004

PEG(poly(ethylene glycol)) acrylate/PPG(poly(propylene glycol)) acrylate (PEG/PPG) was prepared using UV induced photopolymerization method to investigate gas permeation properties of the membrane. The effect of PPG content on the solubility, diffusivity, and permeability of $CO_2$, $O_2$, and $N_2$ in PEG/PPG membrane is reported at $25^{\circ}C$ and $35^{\circ}C$. PEG/PPG (9:1) membrane exhibits $CO_2$ permeability coefficient of 28.9 barrer and $CO_2$/$N_2$ pure gas selectivity of 57.9 at $25^{\circ}C$. Permeability coefficient of increased with increasing with PPG content in the membrane. PEG/PPG (5:5) membrane shows $CO_2$ permeability coefficient of 78.9 barrer and $CO_2$/$N_2$ pure gas selectivity of 33.2 at $25^{\circ}C$.

• Food Science and Preservation
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• v.12 no.6
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• pp.540-545
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• 2005

This study was conducted to evaluate the efficacy of high a)z pre-treatment (60, $100\%$ for 3, 6, 12 hr) on quality of 'Hikawa Hakuho' peach fruits. High a)z treatment inhibited the respiration and ethylene production, especially with long tenn treatment for more than 6 hr. Discoloration of peel, softening and decay were reduced by high $CO_2$ treatment $CO_2$ concentration of $60\~100\%$ did not affect soluble solids content and titratable acidity of fruits. $CO_2$ treated fruits, however, showed higher sweetness score compared with control. As the $CO_2$ concentration and treatment duration increased from 60 to $100\%$ and from 3 to 12 hr, respectively, the efficacy on quality increased. Fruits treated with $100\%\;CO_2$ for 3 hr and $60\%\;CO_2$ for 12 hr, however, showed very low flavor score due to the residual $CO_2$ in flesh. High $CO_2$ injury was not noted at any $CO_2$ levels tested in this study. Above results suggest that $60\%\;CO_2$ treatment for 6 hr resulted in as good control of respiration, ethylene production, decay, discoloration and softening without off-order.