• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.379-382
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• 1997

The effects of different concentrations of ${\alpha}-tocopherol,\;{\delta}-tocopherol$, BHA, BHT and TBHQ on the oxidative stability of perilla oils undergoing autoxidation during storage at $50^{\circ}C$ were studied. ${\alpha}-\;and,\;{\delta}-tocopherols$ were added as concentrations of 100, 200, 300 and 400 ppm to the perilla oils from the unroasted seeds or the roasted seeds at $190^{\circ}C$ for 20 min. BHA, BHT and TBHQ were also added to the perilla oils described above as concentrations of 50, 100, 150 and 200 ppm, respectively. The oxidative stability of perilla oils was estimated by the antioxidative index (AI: the induction periods of oils with antioxidants/the induction periods of oils without antioxidants) on the basis of the peroxide values. The roasted perilla seed oil was more stable than the unroasted seed oil in autoxidation. The addition of ${\alpha}-\;and,\;{\delta}-tocopherols$ accelerated the autoxidation of perilla oils. BHA did not show antioxidant effects, but BHT showed very weak antioxidant effects. The autoxidation of perilla oils, however, was effectively prevented by the addition of TBHQ. TBHQ showed activity in preventing 5 times on the autoxidation of perilla oils. Therefore, the oxidation stability of perilla oils seemed to be depend both on the roasting process and the kind of antioxidants.

• Korean Journal of Food Science and Technology
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• v.50 no.1
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• pp.83-91
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• 2018

Baekseolgi made with arrowroot flour (AF, 0 to 15% of rice flour) was steamed to examine the effect of heating on its antioxidant activity and physicochemical properties. Despite the presence of abundant dietary fiber and superior water-holding capacity of AF, moisture in baekseolgi was not significantly increased. This could partly be attributed to AF having 50% less moisture content than rice flour. Hence, hardness of baekseolgi was also not significantly altered. Total reducing capacity and flavonoid content of baekseolgi increased proportionally with the increase in AF addition. However, these values were lower than the predicted values calculated from the antioxidant activities of heated AF, which was more apparent in total reducing capacity. This indicated that the stability of non-phenolic reducing compounds in AF was lower than that of the phenolic compounds. Thermally processed baekseolgi made with 9% AF exhibited antioxidant activity without noticeable loss in the quality of the product.

• Polymer(Korea)
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• v.30 no.1
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• pp.10-13
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• 2006

The effects of antioxidants and thermal treatment on the radiation resistance of the gamma-ray irradiated polypropylene (PP) were studied. The PP was blended with various antioxidants and was fabricated into a sheet. The PP sheet was irradiated with gamma-ray to a dosage of 25kGy in the nitrogen atmosphere. The differences in both color and mechanical strength were investigated for the gamma-ray irradiated PP depending on the kind and the content of antioxidant. The residual amount of free radical and the variation of oxidation index were investigated for the gramma-ray irradiated PP with thermal treatment after irradiation. The PP having phosphite antioxidant showed little difference in color after gamma-ray irradiation compared with the PP having phenolic or mine antioxidant. Sufficient amount of free radical could be removed from the gamma-ray irradiated PP by the thermal treatment at $130\;^{\circ}C$ for 30 min. Thermally treated PP showed lower oxidation index than the PP without thermal treatment.

• Journal of the Korean Chemical Society
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• v.24 no.5
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• pp.337-341
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• 1980

Radical formation reaction of phenolic antioxidants were examined MO theoretically. Results show that substitution of electron-donating alkyl groups in phenol increases the rate of phenoxy radical formation when attacked by an electrophilic radical by stabilization of cationic transition state.

• Elastomers and Composites
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• v.34 no.4
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• pp.341-349
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• 1999

In this study, heat and crack resistance of natural rubber (NR) compounds was evaluated. To prevent the effects of the crosslinking system, a conventional vulcanization system was selected, where the accelerator/sulfur ratio was fixed to 0.25. Vulcanizates containing phenylenediamine showed high tensile strength and tear strength compared to other vulcanizates because phenylenediamine can cause additional crosslinking and high dispersion In the vulcanizates. In the pure shear test, vulcanizates containing phenylenediamine showed an excellent tearing energy which was due to the irregular crack path, and showed excellent heat and crack resistance which was also due to the good dispersity of antioxidant and additional crosslinks in the rubbber vulcanizates.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.198-202
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• 2018

The present study aimed to investigate the effect of germination and temperature on the antioxidant activity of coffee. Green beans were germinated at 20 and $40^{\circ}C$. Germinated green beans were dried and roasted. Ground coffee was brewed at $90^{\circ}C$ for 5 min. Coffee samples were analyzed for antioxidant compounds and for its antioxidant activity. The total polyphenol content (TPC) and total flavonoid content (TFC) in coffee brewed with coffee beans germinated at $20^{\circ}C$ (CG20) were significantly higher than those in coffee brewed with non-germinated coffee beans (CNG). The same tendency was observed on 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging assays. TPC and TFC of coffee brewed with germinated coffee beans decreased with an increase in germination temperature from 20 to $40^{\circ}C$. In conclusion, germination of coffee beans contributes to an increase in its antioxidant activity. However, setting the appropriate temperature for germination is an important factor in determining the antioxidant activity of coffee.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.111.1-111.1
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• 2016

진공 중 산화처리 방법으로 스테인레스강 표면에 형성한 크롬 산화막에 의한 수소 기체방출 저감 효과를 수치해석 방법으로 분석하였다. 스테인레스 강 진공 용기를 진공 중 산화처리하면 표면의 확산 방지막 효과에 의하여 수소 기체방출률을 낮출 수 있다고 알려져 있으나 그 구체적인 원리는 명확하지 않다. 표면 크롬 산화막의 수소 확산계수가 스테인레스 강 내부의 확산계수보다 작으므로 수소의 확산을 지연시켜 기체방출을 낮춘다는 설명이 가능하지만, 크롬 산화막의 두께 및 확산계수가 미치는 영향을 정량적으로 분석한 예는 없었다. 본 발표에서는 스테인레스강 진공용기의 크롬산화막과 모재 내부에 서로 다른 확산계수를 부여한 후 기체방출에 관여하는 확산 방정식을 수치해석으로 풂으로써, 표면의 확산 방지막에 의한 기체방출 저감 효과를 설명하고자 한다.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.543-548
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• 2018

The current study examined antioxidant and neuronal cell protective effects of the crude polysaccharide fraction in Cudrania tricuspidata fruits (CTP). The radical scavenging activities of (1,1-diphenyl-picrylhydrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)) and reducing power and FRAP of CTP were increased dose-dependently. In addition, the expression of neuroprotective effect of CTP was tested in HT22 mouse hippocampal cells. CTP treatment exhibited non cytotoxicity at dose levels below $500{\mu}g/mL$. Within this optimal concentration range, CTP treatment significantly increased cell viability in $H_2O_2-treated$ HT22 cells. Furthermore, CTP treatment increased superoxide dismutase (SOD) activity and decreased malonaldehyde (MDA) levels in HT22 cells. Therefore, these results indicate that the crude polysaccharide fraction from Cudrania tricuspidata fruits (CTP) possesses antioxidant activities and displays therapeutic potential as a useful source material in the development of brain disorder treatments targeting oxidative stress in neuronal cells.

• Tribology and Lubricants
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• v.6 no.2
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• pp.1-15
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• 1990

본 해설에서는 윤활 오일에서 구리 반응 억제제와 철의 부식 억제제에 관한 내용을 검토한 것으로 자동산화 화정의 초기 생성과 연쇄적인 전파, 확산 및 종료 그리고 1차 및 2차 산화 억제제에 관해서 서술한 것이다. 구리 반응 억제제와 부식 억제 성질 및 작용이 고려되고 첨가제로써의 응용에 관해 조사하였다.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.75-85
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• 2004

목적 : 黃芩(황금)과 黃芩(황금)의 주요 flavonoid 성분인 baicalein이 신장세뇨관 상피세포에서 산화제에 의한 apoptosis에 미치는 효과를 살펴보고자 한다. 방법 : 신장세뇨관 상피세포주인 opossum kidney (OK) 세포를 유기산화제인 t-butylhydroperoxide (tBHP)에 노출시켜 apoptosis를 일으킨 후 관련된 변화를 관찰하였다. 결과 : tBHP는 농도에 의존하여 apoptosis를 유발시켰는데, 이러한 효과는 黃芩(황금)과 baicalein에 의해 농도 의존적으로 방지 되었다. tBHP에 의한 OK 세포사는 항산화제인 Trolox와 N-acetylcysteine에 의해 방지 되었다. tBHP는 mitogen-activated protein kinase의 subfamily인 extracellular signal-regulated kinase (ERK)를 활성화시켰다. ERK 억제제인 PD98059와 U0126은 tBHP에 의한 세포 사망을 방지하였다. tBHP에 의한 ERK 활성화는 U0126에 의해 억제되었으나 黃芩(황금)과 baicalein에 의해서는 영향을 받지 않았다. 철착염제인 deferoxamine은 tBHP에 의한 세포 사망과 ERK 활성화를 방지하였다. tBHP에 의한 세포 사망은 casopase 억제제인 BOD-U-FMK와 zDEVD-FMK에 의해 방지되었다. 결론 : 黃芩(황금)은 산화제에 의한 세포 사망을 방지하는데, 이는 kinase 억제, 항산화제 역할 및 철착염제의 작용에 기인하지 않았다. 黃芩(황금)의 이러한 효과는 산화제에 의관 신부전 예방 및 치료제로 개발하는데 이용될 수 있는 가능성을 보였다.