• 한국축산식품학회지
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• 제44권2호
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• pp.408-429
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• 2024

The color, lipid oxidation, heme iron (HI) and non-heme iron (NHI) contents, metmyoglobin content and Soret band of myoglobin of ground pork subjected to supercritical CO₂ treatment under different conditions, or to heat treatment (40℃, 2 h) and subsequent storage at 4℃ were evaluated during 9-day period. Supercritical CO₂ treatment significantly increased CIE L^* and CIE b^* values of ground pork during subsequent storage, while the HI content was slightly affected. In general, CIE a^* value and metmyoglobin content were decreased. Supercritical CO₂ treatment for 2 h could increase the thiobarbituric acid-reactive substances (TBARS) value, while treatment for 1 h or less had no effect. The NHI content could be increased only after treatment at above 40℃ or 17.2 MPa for 2 h. The Soret band of myoglobin was shifted to longer wavelength. Increasing treatment temperature from 35℃ to 45℃ could increase CIE L^*, CIE a^*, CIE b^* and TBARS values, HI and NHI contents of the ground pork, while decreasing metmyoglobin content. As the treatment pressure increased from 13.8 MPa to 20.7 MPa, CIE b^* and TBARS values were decreased, while the NHI and metmyoglobin contents were increased. However, the other parameters were unchanged. Extending exposure time from 0.5 h to 2 h could increase CIE L^*, CIE b^* and TBARS values, HI contents, while decreasing CIE a^* value and metmyoglobin content. Correlation analysis showed that the TBARS value was significantly and negatively correlated with the HI content or metmyoglobin content in samples treated at 40℃ or above for 2 h.

• 한국식품영양과학회지
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• 제37권10호
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• pp.1330-1336
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• 2008

본 연구는 고품질의 동치미 제조를 위해 고온살균에서 발생될 수 있는 향기 성분의 변화와 영양소 파괴 등으로 인한 품질저하의 문제점을 해결하기 위해 비열처리 공정인 초임계 이산화탄소를 이용하였으며 이화학적 품질특성을 조사하였다. 그 결과 pH, 산도 및 색도는 상압에서 가열처리한 동치미와 초임계 이산화탄소를 처리한 동치미 모두 뚜렷한 변화를 나타내지 않았으며 비타민 C의 경우 초임계 이산화탄소 처리구가 상압에서 가열처리한 구간보다 더욱 안정함을 보였다. 유기산과 유리당의 경우는 초임계 이산화탄소 처리구가 상압에서 가열처리한 구간보다 다소 낮은 함량을 보였으나 그 차이는 매우 적음을 알 수 있었다. 휘발성 향기 성분은 dimethyl disulfide, methyl trisulfide, methyl propyl disulfide 등 마늘과 파 등의 특유의 강한 향기성분들은 초임계 이산화탄소처리에 의해 대부분 감소됨을 보여주었다. 초임계 이산화탄소를 이용하여 동치미 무의 polygalacturonase 효소를 불활성화 시키기 위해서는 25 MPa 이상의 압력과 $55^{\circ}C$ 이상의 온도가 요구됨을 확인하였다. 따라서 동치미의 살균을 위해 초임계 이산화탄소를 처리함으로써 동치미 중 PGase 효소의 불활성화가 가능하며, 산업적 응용을 위해서는 무를 제외하고 동치미 액만을 활용하는 것이 용이하다 사료된다.

• 한국축산식품학회지
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• 제33권5호
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• pp.581-586
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• 2013

The objective of this study was to investigate the effects of supercritical carbon dioxide (SC-$CO_2$) treatment on meat quality and sensory evaluation of marinated pork. Meat marinated in two traditional Korean marinades, soy sauce and hot-pepper paste, and raw marinated meat were then treated with 7.4, 12.2, or 15.2 MPa $CO_2$ at $31.1^{\circ}C$for 10 min. The SC-$CO_2$ treatments had no effect on the meat pH (p>0.05) or Warner-Bratzler shear force (p>0.05). There was no significant difference (p>0.05) in the total loss (sum of treatment loss and cooking loss) between the control and SC-$CO_2$ treated samples at 15.2 MPa (soy sauce marinated pork: 21.78 vs. 18.97%; hot-pepper marinated pork: 21.61 vs. 18.01%). After the SC-$CO_2$ treatment, lighter surface colors were observed in the treatment samples compared to those of the control samples (p< 0.001). However, tasting panelists were unable to distinguish a difference in color or in overall acceptability of the control and treatment (p>0.05). In the case of soy sauce marinated pork, when SC-$CO_2$ applied at 15.2 MPa and $31.1^{\circ}C$for 10 min, treatment samples showed a tenderer meat than the control samples. Therefore, the SC-$CO_2$ treatment conditions had no adverse effects on the sensory quality characteristics of the marinated meat products.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.235-243
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• 2008

The aim of this study is to explore the possibility of incorporating supercritical carbon dioxide ($scCO_2$) into twin screw extrusion process for the production of polypropylene-clay nanocomposite (PPCN). The $CO_2$ is used as a reversible plasticizer which is expected to rapidly transport polymeric chains into the galleries of clay layers in its supercritical condition inside the extruder barrel and to expand the gallery spacings in its sub-critical state upon emerging from die. The structure and properties of the resulting PPCNs are characterized using wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), rheometry, thermogravimetry and mechanical testing. In the processing of the PPCNs with $scCO_2$, optimum $scCO_2$ concentration and screw speed which maximized the degree of intercalation of clay layers were observed. The WAXD result reveals that the PP/PP-g-MA/clay system treated with $scCO_2$ has more exfoliated structure than that without $scCO_2$ treatment, which is supported by TEM result. $scCO_2$ processing enhanced the thermal stability of PPCN hybrids. From the measurement of linear viscoelastic property, a solid-like behavior at low frequency was observed for the PPCNs with high concentration of PP-g-MA. The use of $scCO_2$ generally increased Young's modulus and tensile strength of PPCN hybrids.

• 한국식품저장유통학회지
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• 제16권4호
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• pp.482-489
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• 2009

본 연구에서는 초임계 이산화탄소를 이용하여 동치미의 살균 특성과 효소불활성화에 대한 조사를 하였다. 초임계 이산화탄소를 처리한 동치미의 생균수 및 젖산균은 초임계 이산화탄소의 온도와 압력이 증가하면 사멸 속도가 증가하여 사멸속도는 1차 반응식을 따랐다. D-값의 경우 초임계상태에서 온도가 압력보다는 더 큰 영향을 주는 것으로 나타났으며 젖산균의 경우 25MPa, $25^{\circ}C$의 초임계상태에서 가장 낮은 D-값과 생균수를 나타내었고 PGase도 40.3%가 실활 되었다. 이상의 결과로 초임계이산화탄소는 미생물의 살균 및 효소실활을 위한 또 하나의 비열처리기법으로 이용될 수 있음을 확인하였다.

• Food Science and Biotechnology
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• 제18권1호
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• pp.66-72
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• 2009

An aqueous ribose-cysteine model system (initial pH 5.6) was conventionally heated to the same browning at varying temperatures ($120-180^{\circ}C$), supercritical carbon dioxide (SC-$CO_2$, 20 MPa) was also applied on the same matrices for same periods at each temperature and about 20% reduction of the absorbance at 420 nm was observed as compared with sole thermal treatment. The headspace volatiles from Maillard reaction mixtures were analyzed by solid-phase microextraction (SPME) in combination with gas chromatography and mass spectrometry (GC-MS), and predominated with sulfur containing compounds, such as thienothiophenes, polysulfur alicyclics, thiols, and disulfides. Reaction temperature exhibited complex effects on volatiles formation and those effects became further complicated by the SC-$CO_2$ treatment. The formation of noncarbonyl polysulfur heterocyclic compounds and thienothiophenes was generally favored at high temperatures. Most volatiles were inhibited in SC-$CO_2$ as compared with thermal treatment alone, however, the well-known meaty aromatic compounds, such as thiols and disulfides, were obviously enhanced.

• 한국표면공학회지
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• 제37권6호
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• pp.344-349
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• 2004

Emulsions were formed through putting small quantity of nickel electroplating solution into supercritical carbon dioxide, and then electroplating in the $sc-CO_2$ emulsions was conducted. It is an environmental-friendly technology that can solve the treatment of a large quantity of toxic plating wastewater, which is a big problem in the existing wet plating, and also can reduce secondary waste generation fundamentally. Supercritical carbon dioxide emulsions enhanced by ultrasonic horn were formed by non-ionic surfactant and nickel solution. Plating condition within emulsions was set up as 120bar and $55^{\circ}C$ through measurement of electrical conductivity following the pressure change. Experiments were conducted respectively against supercritical carbon dioxide emulsions electroplating and general chemical electroplating, and then their results were compared and analyzed. As the experiment result utilizing emulsions, plating surface was formed very evenly even with a small quantity of electroplating solution, and fine particles were plated compactly without any pinhole or crack due to hydrogenation, which occurs in general electroplating. Used electroplating solution can be reused through recovery process. Therefore, this technology will be able to be applied as new clean technology in electro-plating.

• 한국염색가공학회지
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• 제31권1호
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• pp.48-64
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• 2019

With evolution in the production environment of the textile industry, the need for non-water-based dyeing technologies and eco-friendly process facilities in the dyeing and processing stages has increased. In recent years, supercritical fluid dyes have been developed and commercialized in Europe, centering on this demand. However, so far, such dyes have been mainly applied in the processing of PET fibers. Basic research has mainly involved investigation of dyeing by supercritical carbon dioxide or solubility of such dyes, and more in-depth research should be continuously carried out. In this review, we describe the types and characteristics of supercritical fluids that exhibit specific properties at pressures and temperatures over the critical point. In addition, the state of the art in the dyeing and processing technology using supercritical fluids and associated, processing problems, environmental regulation, and wastewater treatment issues are described in detail. We hope this review can contribute to the supercritical fluid technology being further developed as an environment friendly dyeing processing method. Furthermore, we expect that the technique can be used as a means of ensuring different, high-quality dyed products.

• Journal of the Korean Wood Science and Technology
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• 제28권4호
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• pp.41-50
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• 2000

Cement-bonded particleboard is being used as outdoor siding material all over the world, because this composite particularly bears a light weight, high resistance against fire, decay, and crack by cyclic freezing and thawing, anti-shock property, and strength enhancement. Construction systems are currently changing into a frame-building style and wooden houses are being constructed with prefabrication type. Therefore, they require a more durability at outdoor-exposed sides. In this study, the cement hydration property for Korean pine particle, Japanese larch particle and face- and middle layer particles (designated as PB particle below) used in Korean particleboard-manufacturing company was investigated, and the rapid manufacturing characteristics of cement-bonded particleboard by supercritical $CO_2$ curing was evaluated. Korean pine flour showed a good hydration property, however, larch flour showed a bad one. PB particle had a better hydration property than larch flour. The addition of $Na_2SiO_3$ indicated a negative effect on hydration, however, $MgCl_2$ had a positive one. Curing by supercritical $CO_2$ fluid gave a conspicuous enhancement in the performances of cement-bonded particleboards compared to conventional curing. $MgCl_2$ 3%-added PB particle had the highest properties, and $MgCl_2$ 1%-added Korean pine particle had the second class with the conditions of cement/wood ratio of 2.7, a small fraction-screened particle and supercritical curing. On the contrary, the composition of non-hammermilled or large fraction-screened particle at cement/wood ratio of 2.2 was poorer. Also, the feasibility for actual use of 3%-added, small PB particle-screened fraction was greatest of all the conventional curing treatments. Relative superiority of supercritical curing vs. conventional curing at dimensional stability was not so apparent as in strength properties. Through the thermogravimetric analysis, it was ascertained that the peak of a component $CaCO_3$ was highest, and the two weak peaks of calcium silicate hydrate and ettringite and $Ca(OH)_2$ were present in supercritical treatment. Accordingly, it was inferred that the increased formation of carbonates in board contributes to strength enhancement.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.586-591
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• 2001

This research investigated the feasibility of the accelerated carbonation of cement waste forms with carbon dioxide in a supercritical state. Hydraulic cement has been used as a main solidification matrix for the immobilization of radioactive and/or hazardous wastes. As a result of the hydration reaction for major compounds of portland cement, portlandite (Ca(OH)$_2$) is present in the hydrated cement waste form. The chemical durability of a cement form is expected to increase by converting portlandite to the less soluble calcite (CaCO$_3$). For a faster reaction of portlandite with carbon dioxide, SCCD (supercritical carbon dioxide) rather than gaseous $CO_2$, in ambient pressure is used. The cement forms fabricated with an addition of slated lime or Na-bentonite were cured under ambient conditions for 28days and then treated with SCCD in an autoclave maintained at 34$^{\circ}C$ and 80atm. After SCCD treatment, the physicochemical properties of cement matrices were analyzed to evaluate the effectiveness of accelerated carbonation reaction. Conversion of parts of portlandite to calcite by the carbonation reaction with SCCD was verified by XRD (X-ray diffraction) analysis and the composition of portlandite and calcite was estimated using thermogravimetric (TG) data. After SCCD treatment, tile cement density slightly increased by about 1.5% regardless of the SCCD treatment time. The leaching behavior of cement, tested in accordance with an ISO leach test method at 7$0^{\circ}C$ for over 300 days, showed a proportional relationship to the square root of the leaching time, so the major leaching mechanism of cement matrix was diffusion controlled. The cumulative fraction leached (CFL) of calcium decreased by more than 50% after SCCD treatment. It might be concluded that the enhancement of the characteristics of a cement matrix by an accelerated carbonation reaction with SCCD is possible to some extent.