• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.294.2-294.2
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• 2003

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.517-519
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• 1991

The effect of glucose oxidase (GO) and superoxide dismutase (SOD) on the oxidative stability of fish oil was investigated from oxygen content and peroxide value determinations of oil samples stored in vial. GO could inhibit the oxidation of the oil by removing headspace oxygen. When SOD was solubilized in the oil, peroxide value was slightly lower than that of a control, indicating that the enzyme also had an effect on retarding the oxidation.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.287-292
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• 2012

Light effects on temperature dependence of safflower oil oxidation and tocopherol degradation were studied. Safflower oil was oxidized at 20, 40, 60, or $80^{\circ}C$ for 30, 30, 15, and 6 days, respectively, in the dark or under light. Oil oxidation was evaluated with peroxide value (POV) and conjugated dienoic acid (CDA) value, and tocopherols were monitored by HPLC. Safflower oil consisted of palmitic, stearic, oleic, and linoleic acids at 7.3, 2.0, 14.2, and 76.6%, respectively, with tocopherols at 1157.1 mg/kg. Peroxide and CDA values of safflower oil increased while tocopherol contents decreased with the oxidation time and temperature. Light increased and accelerated the oil oxidation and tocopherol degradation. Temperature dependence of the oil oxidation and tocopherol degradation was higher in the dark rather than under light. The results suggest that temperature control could be more essential in the dark rather than under light with regard to the oxidative stability of safflower oil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.726-731
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• 2001

To enhance the utilization of chestnut husk discarded in the processing company antioxidative activities and compounds were investigated. Antioxidative activities of solvent fractions from chestnut husk were examined by benzoic acid hydroxylation method ferric thiocyanate method and DPPH test. Ethyl acetate fraction showed strong antioxidative activities comparable to BHA. Active compounds were isolated and purified from ethyl acetate fraction by Sephadex LH-20 column chromatography and preparative HPLC. A major active compound gallic acid was identified by $^{1}$H and $^{13}$ C-NMR. The phenolic acid contents was analyzed by GC and ellagic acid (172.22 mg%) and gallic acid (107.39 mg%) were major phenolic acid of chestnut husk.

• Food Industry And Nutrition
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• v.7 no.3
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• pp.44-49
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• 2002

본 연구는 retinyl acetate와 $\beta$-carotene보충식이가 에탄올에 의한 산화적 손상에 미치는 영향을 조사하고자 흰쥐에게 비타민 A와 $\beta$-carotene을 보충한 식이를 5주간 급여한 후 에탄올을 급성으로 투여하여 혈청과 간 조직에서 생성되는 지질과 지질과산화물 함량 그리고 glucose-6-phosphatase 활성도를 측정하였다. 본 실험에서 얻은 결과를 요약하면 체중 증가량은 전 실험군에서 유의적인 차이없이 실험 기간 동안 증가되었으며 사료섭취량과 식이효율을 그리고 간 중량 역시 각 군 모두 유의적인 차이를 나타내지 않았다. 혈청 중성지질 함량은 대조군과 retinyl acetate 보충군에서 높은 함량을 보였으나 통계적인 유의성은 없었다. 총 콜레스테를 함량은 대조군과 $\beta$-carotene 보충군은 비슷한 수준을 나타낸 반면 retinyl acetate 보충군에서는 유의적으로 감소되었다. HDL-콜레스테롤 함량은 대조군에서 가장 높았으며 LDL-콜레스테롤 함량은 유의적이지는 않았으나 retinyl acetate 보충군에서 가장 낮은 함량을 보였다. 동맥경화지수는 전 실험군에서 유의적인 차이는 없었으나 retinyl acetate 보충군에서 가장 낮았다. 간 마이크로솜 내에서 지질과산화물 함량은 재도군에 비하여 $\beta$-carotene 보충군에서 유의적으로 감소되었다. Retinyl acetate와 $\beta$-carotene 보충군 사이에서는 유의적인 차이가 없었으나 급성적인 에탄올 투여시에 $\beta$-carotene의 보충 급여가 지질과산화반응에 방어효과가 있는 것으로 나타났다. 간 조직중의 glucose-6-phosphatase 활성도는 비타민을 정상적으로 공급시킨 대조군이 retinyl acetate나 B-carotene 보충군에 비하여 유의적으로 높았으며 retinyl acetat와 B-carotene 보충군 사이에는 유의적인 차이가 없었다.

• The Korean Journal of Mycology
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• v.23 no.1 s.72
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• pp.86-91
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• 1995

Isoenzymatic analysis related with cadmium adaptation and detoxifying mechanism were carried out upon Rhizopus oryzae. When cadmium was added into R. oryzae culture, activities of malate dehydrogenase (MDH) and glucose phosphate isomerase (GPI) related with carbohydrate metabolizing pathways were stimulated. Novel isoenzyme CAT-2 related with removing intracellular toxic peroxides, was induced lately and derepressed very highly. On the other hand, lactate-catabolizing enzymes such as lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH) were repressed. These results strongly suggest that, under cadmium stress, much of derepression of enzymes relating with central metabolism such as TCA cycle that produces high yield of energy and relating with removal of toxic peroxides should be necessary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1065-1070
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• 2016

This study assessed the antioxidant activity and residue level of phenolic antioxidants in autoxidation of linoleic acid. The antioxidant activity of phenolic antioxidants was measured based on peroxide value of linoleic acid at $50^{\circ}C$ for 8 days. We further evaluated the residue level of phenolic antioxidants in the autoxidation period by HPLC-UV. The residue level of antioxidants changed with time starting on day 0 (100%) and was determined by 100-remaining of antioxidants (%). Our results showed that peroxide values ranged from 0.33 to 10.18 meq/kg in propyl gallate, from 0.67 to 11.01 meq/kg in dodecyl gallate, from 0.01 to 10.34 meq/kg in octyl gallate, from 0.01 to 4.17 meq/kg in butylated hydroxytoluene (BHT), from 1.00 to 5.85 meq/kg in butylated hydroxyanisole (BHA), from 0.33 to 4.18 meq/kg in 2,4,5-trihydroxybutyrophenone, and from 1.00 to 11.01 meq/kg in tert-butylhydroquinone (TBHQ). Among the residue levels of antioxidants, on day 8, BHT showed the highest level while TBHQ showed the lowest. BHT showed the highest correlation coefficient, whereas BHA showed the lowest. This study proves that the residual level of phenolic antioxidants has a good correlation with the degree of autoxidation in linoleic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1640-1648
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• 2009

This study was carried out to investigate the antioxidant activity of bamboo (Sasa borealis) leaf extract by measuring electron donating ability, superoxide dismutase (SOD)-like activity, reducing power, and lipid peroxidation inhibitory activity. Two crude extracts by water or 70% EtOH and five fractions of n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous from the crude extract of 70% EtOH were prepared for this study. The crude extracts of water and 70% EtOH yielded 8.5% and 11.4%, respectively and the yields of n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous fractions were 5.1% to 0.6%. Total polyphenol contents of the water and the 70% EtOH crude extracts were not significantly different; however, their total flavonoid contents were significantly greater in the 70% EtOH than in the water crude extract. Total polyphenol contents were the highest in chloroform fraction followed by ethyl acetate and n-butanol fractions and total flavonoid contents were the highest in ethyl acetate fraction followed by chloroform and n-hexane fractions. The two crude extracts as well as the five fractions showed election donating ability, SOD-like ability, reducing power, and lipid peroxidation inhibitory activity. Most of the antioxidant activities of each crude extract or fractions increased proportionally with the concentration. These results indicate that bamboo (Sasa borealis) leaf extracts show antioxidant activities due to its substantial content of polyphenol including flavonoid. Thus, it could be concluded that crude extracts by water or 70% EtOH and the fractions from the 70% EtOH extract, especially chloroform, ethyl acetate and n-butanol, would be useful as natural antioxidant substances.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.418-427
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• 2003

Conjugated linoleic acid (CLA) is the mixture of positional and geometric isomers of linoleic acid (LA, C18:2 $\omega$6), which is found abundantly in dairy products and meats. This study was peformed to investigate the anticarcinogenic effect of CLA in MCF-7 breast cancer cells. MCF-7 cell were treated with LA and CLA at the various concentrations of 15, 30, 60, 120 UM each. After incubation for 48 and 72 hours, cell proliferation, fatty acids incorporation into cell, peroxidation and activities of antioxidant enzymes were measured. Postaglandin E$_2$ (PGE$_2$) and thromboxane $A_2$ (TXA$_2$) were measured for the eicosanoids metabolism. There was no cell growth differences in both of LA and CLA treated MCF-7 cells at 48 hr incubation. Compared to LA, cell growth was decreased by CLA treatment according to increasing concentration at longer incubation times, respectively (p<0.05). Both of LA and CLA was incorporated into the cellular lipids 22~54% higher than in control but LA incorporation was not so linear as CLA according to concentration. Arachidonic acid (C20:4, $\omega$6) was synthesized after treatment of LA but did not in CLA, respectively. The lipid peroxide concentration in LA 120 $\mu$M group increased as 1.7 times as that in CLA 120 $\mu$M treated. The activities of antioxidant enzymes such as glutathione peroxidase and glutathione reductase were increased by the supplementation with CLA 120 $\mu$M at 72 hr incubation (p<0.001) compared to LA, otherwise activity of superoxide dismutase was not different in both. PGE$_2$ and TXA$_2$ levels were lower in condition of CLA treatments according to lower levels of arachidonic acids than those in LA treated group, respectively. Overall, the dietary CLA might change the MCF-7 cell growth by the changes of cell composition, production of lipid peroxide, activities of antioxidant enzymes and eicosanoid synthesis compared to dietary LA.

• Food Science and Preservation
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• v.22 no.6
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• pp.845-850
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• 2015

The influence of different roasting temperatures, times and extraction methods on the quality characteristics of Omija (Schizandra chinensis) seed oils was investigated. Roasted Omija seeds were divided into five groups based on roasting temperature-time conditions: no roasting (Raw) and roasting [R11: $150^{\circ}C$, 10 min, R12: $150^{\circ}C$, 20 min, R21: $250^{\circ}C$, 10 min, R22: $250^{\circ}C$, 20 min (R22)]. Oils from each of the raw and roasted Omija seeds were obtained by solvent (n-hexane) and press (machine) extraction. The $L^*$ values decreased, but the $a^*$ and $b^*$ values increased with increasing the roasting temperature and time. The $L^*$ values were lower in the press-extracted oils than in the solvent-extracted oils. The peroxide value (POV) of Omija seed oils decreased with increasing the roasting temperature-time values. The POV value was higher in the press-extracted oils than in the solvent-extracted oils. ABTS (2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical inhibition of Omija seed oils was higher in the solvent-extracted oils than in the press-extracted oils, but there were no significant differences between the two oils. The four major kinds of fatty acid methyl esters detected in Omija seed oils were methyl butyrate, methyl hexanoate, methyl arachidate, and methyl eicosanoate. In conclusion, Omija seed oils obtained by solvent extraction and at higher roasting temperature-time values were more effective antioxidants.