• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1018-1023
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• 2010

This study was conducted to investigate quality changes of apple slab after pretreating with supercritical $CO_2$. L, a, b and color difference values were little changed at increasing temperature and pressure. Polyphenol oxidase was inhibited according to increment of supercritical $CO_2$ temperature and pressure. Springiness and hardness were increased at increasing pressure and temperature condition of pretreatment but hardness showed lower value than untreatment. The texture like sponge of dried apple slab was probably due to channels which were made during penetration and release of carbon dioxide.

• KSBB Journal
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• v.18 no.5
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• pp.385-392
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• 2003

Biodegradable poly (L-lactide) (L-PLA) solution in methylene chloride was precipitated into microparticles by using supercritical carbon dioxide modified with polar cosolvents. The effects of the amount of polar cosolvents, solution concentration, temperature, and solution flow rate on the formation of microparticles were investigated. The mean particle size was found to increase with the increase of solution concentration and flow rate. It was also observed that the particle size not only increases but the size distribution also becomes less uniform as the temperature increases. The percent recovery of microparticles was found to be 30∼40% at all experimental conditions. The supercritical carbon dioxide modified with methanol and ethanol was employed to enhance the recovery, resulting in significant improvement up to about 80 and 70%, for methanol and ethanol, respectively. Furthermore, the mean diameter of L-PLA microparticles was found to be less than 1 $\mu\textrm{m}$ for both cosolvents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1330-1336
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• 2008

Here we studied the changes on quality characteristics of Dongchimi by supercritical carbon dioxide to manufacture Dongchimi of high quality. There were no distinctive changes of acidity, pH, color difference, free sugar and organic acid of the Dongchimi treated with supercritical $CO_2$, compared to the control. The content of vitamin C in Dongchimi, which was treated with supercritical $CO_2$ (at 25 MPa, $35^{\circ}C$) was 0.826 mg/mL, and was similar to that of 0.1 MPa. Unpleasant volatile compounds such as dimethyl disulfide, metyl trisulfide and methyl propyl disulfide in Dongchimi were decreased by supercritical $CO_2$; also, treatment of supercritical $CO_2$ was useful to improve flavor of Dongchimi. Polygalacturonase activity was decreased 40.3% after supercritical carbon dioxide treatment at 25 MPa and $55^{\circ}C$.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.227-230
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• 2004

본 연구에서는 신선육 및 원료육의 미생물 저감화 및 안전성 확보를 위해 식육에 초임계 이산화탄소 처리를 실시하였다. 이산화탄소의 초임계점인 78 atm, $38^{\circ}C$에서 10분 처리한 시료에서 병원성 미생물의 저감화가 나타나기 시작했으며, 압력을 100 atm 이상으로 증가시켰을 때 5 log 이상의 억제 효과가 나타나 신선육 및 원료육의 미생물학적 안전성이 검증되었다. 하지만 초임계 이산화탄소의 압력을 증가시킬수록 안정성은 확보되는 반면 시료의 구조${\cdot}$물성 변이가 심화되어 원료육의 가공적성도는 떨어지는 것으로 판단된다. 따라서 신선육 및 원료육의 품질을 고려한 미생물적 안전성을 확보하려면, 이산화탄소의 초임계점수준의 처리가 요구되며, 향후 초임계 이산화탄소 처리에 따른 육질변이 및 가공적성도에 대한 다각적이고 심도 있는 연구가 요구된다.

• Journal of the KSME
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• v.55 no.7
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• pp.42-45
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• 2015

초임계 이산화탄소는 환경친화적 유체로서 많은 장점을 갖고 있고, 기화시켜 재사용할 경우 2차 폐기물의 발생이 없는 우수한 용매이다. 이 글에서는 초임계 이산화탄소를 이용하여 방사성 오염물을 제염(除染, decontamination)하는 기술을 소개하고자 한다.

• 기계와재료
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• v.26 no.1
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• pp.38-46
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• 2014

초임계 이산화탄소 사이클 발전시스템은 액체와 기체의 복합 특성을 가지는 초임계 유체의 특성을 잘 활용하여 고효율 및 고출력의 장점을 가지며, 다양한 열원을 이용한 발전이 가능하기 때문에 최근 차세대 발전기술로서 주목을 받고 있다. 미국, 일본 등 선진국에서는 현재 실험실 규모의 시스템 검증을 거쳐 수십 MWe급 시스템 개발을 진행 중에 있으며 수백 MWe급 플랜트를 구축하는 프로젝트도 준비 중에 있다. 본 고에서는 이러한 초임계 이산화탄소 사이클 발전시스템의 기술적 특징과 기술개발 동향을 소개하고, 특히 향후 분산형 발전시스템으로 적용 가능성을 제시하고자 한다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.20-24
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• 2010

This study was performed to investigate antioxidant activities of Mistletoe (MS) extracts by measuring electron donating ability (EDA), super oxide dismutase (SOD)-like activity and total polyphenol content (TPC). The extracts were obtained using supercritical carbon dioxide, hot-water and ethanol extraction. EDAs was the higher in ethanol extract (70.53%) than water (36.73%) or supercritical carbon dioxide extract (15.73% at 400 bar, $30^{\circ}C$) at concentration of 10 mg/mL. However, SOD-like activities and TPCs were the highest in the supercritical carbon dioxide extract. At concentration of 1 mg/mL, supercritical carbon dioxide extract (22.54% at 200 bar, $40^{\circ}C$) was higher SOD activity than water (7.85%) and ethanol extract (6.12%). Regarding TPCs of MS extracts, the content was the highest in supercritical carbon dioxide extract (17.57 wt% catechin equivalent at 200 bar, $50^{\circ}C$) followed by ethanol and water extract. These results suggest that it can be useful to develop functional foods using antioxidative active compounds of MS with high polyphenol contents.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.251-257
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• 2011

In the present study, a 3-dimensional (3D) numerical model was developed to mimic the micro porous structure of a geological $CO_2$ storage reservoir. Especially, 3D modeling technique assigning random pore size to a 3D micro porous structure was devised. Numerical method using CFD (computational fluid dynamics) was applied for the 3D micro porous structure to calculate supercritical $CO_2$ flow field. The three different configurations of 3D micro porous model were designed and their flow fields were calculated. For the physical conditions of $CO_2$ flow, temperature and pressure were set up equivalent to geological underground condition where $CO_2$ fluid was stored. From the results, the characteristics of the supercritical $CO_2$ flow fields were scrutinized and the influence of the micro pore configuration on the flow field was investigated. In particular, the pressure difference and consequent $CO_2$ permeability were calculated and compared with increasing $CO_2$ flow rate.

• Food Science and Preservation
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• v.17 no.2
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• pp.256-260
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• 2010

We investigated changes in the chemical composition of apple slices after pretreatment with supercritical $CO_2$. Total phenolic levels increased with increasing temperature, although the concentrations were lower in pretreated material than in fresh or untreated slices. The levels of vitamin C and malic acid in pretreated slices were also lower than in untreated or fresh apple slices. Little difference was evident among various pretreatmentconditions. It was found that supercritical $CO_2$ served not as a solvent but rather as a means of tissue compression. Supercritical $CO_2$ compressed the apple slices, causing juice to be extruded. The juice disappeared when the supercritical $CO_2$ pressure was released.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.360-362
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• 2012

본 논문에서는 의약품, 화장품, 생활용품에서 널리 사용되는 약물인 트리클로산에 대해 초임계 유체를 이용하여 미세화공정이 연구되었다. 낮은 임계온도와 임계압력의 조건을 고려하여 초임계 이산화탄소를 선정하였고, 초임계 이산화탄소와의 용해도를 고려하여 초임계 용액 급속팽창공정이 선정되었다. 본 연구에서 입자크기에 영향을 미치는 온도와 압력효과가 검토되었고 상평형자료에 의해 해석되었다.