• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.899-907
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• 1994

Accumulation of peroxidized lipid, fed or injected in the body of rats was investigated and the effect of peroxidized lipid on the antioxidative system was studied also. Three groups each having six of Sprague-dawley rats were raised for 8 weeks. the peroxide value(POV) of diet fed to the control and the peroxidized group was 5.47 and 22.14meq/kg , respectively. Injected group was given the control diet and peroxidized linoleic acid(POV 31.81meq/kg) was injected into the peritoneal area three times a week. The POV, MDA, and protein carbonyl values of the peroxidized and the injected group (experimental groups) were significantly higher (p<0.05) than those of the control group. Cu, Zn-SOD and M-SOD activity of the experimentla groups increased 1.6 times that of control group at 4 th week. and decreased by 60% of their activityafter 8 weeks of feeding (p<0.05) . Catalase activity, glutathione and Vt, E contents of the experimental groups were significantly lower (p<0.05) than those of the control group during 8 weeks. The accumulation of peroxidcized lipid in liver were ovserved both in the fed or the injected group. The increased of enzyme activity of the experimental group during 4 weeks suggests ianadaptation of antioxidative system to get rid of the peroxidized lipid. Decrease of enzyme activity and glutathione observed as the peroxidized lipid lipid accumulation proceeded further, however, seems to indicate the oxdiative damage of enzyme and protein . Determination of the protein carbonyl content may be used as a method for measuring the oxidative damaging effect of peroxidized lipid.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.628-635
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• 2009

Autoxidative stability of wheat bran and germ oil extracted from Keumkang wheat (WBG-K) or Dark Northern Spring wheat (WBG-DNS) at $50^{\circ}C$ in the dark was compared by peroxide values (POV) and fatty acid composition by gas chromatography. Changes of minor compounds were monitored by HPLC. WBG-K showed significantly higher linoleic but lower oleic acid content than WBG-DNS. WBG-DNS contained more phospholipids but less tocopherols and carotenoids than WBG-K. POV of oils was increased during storage, with no significant difference in the oxidation rates between two oils. Tocopherols, carotenoids, and phospholipids in both oils were degraded during the autoxidation. Total phospholipids content showed the highest correlation with the degree of oxidation in WBG oils. The results clearly showed that both fatty acid composition and contents of tocopherols, carotenoids, and phospholipids co-affected the autoxidation of WBG oil.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.461-464
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• 2004

Antioxidant artivity of Maesil (Prunus mume) was evaluated based on peroxide value (POV), thiobarbiturie acid reactive substances (TBARS value), and electron-donating ability using 1,1-diphenyl-2-pycryl hydrazil (DPPH) method. POVs for soybean oil with 0.02% antioxtdants were 276.93, 223.32, 217.38, 238.40, and 226.55 meq/kg in control, ascorbic acid, dibutyl hydroxytoluene (BHT), extract of dehydrated Maesil flesh (EDMF), and extract of dehydrated Maesil juice (EDMJ), respectively, Antioxidant activities for TBA values were 29.94. 45.35 13.81, and 25.00% In ascorbic acid, BHT, EDMF, and EDMJ, respectively. Electron-donating abilities by DPPH were 96.69, 77.82, 34.84, and 43.50% in ascorbic acid, BHT, EDMF, and EDMJ, respectively, EDAs by DPPH with 0.02% EDMF and EDMJ were 53.21 and 59.19%, respectively.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.203-207
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• 1993

Free phenolic acid, soluble ester and insoluble phenolic acid were extracted from defatted Crataegus pinnatifida and Terminalia chebula. Their antioxidative effectiveness was compared with BHA and BHT for soybeen oils by measuring peroxide and thiobarbituric acid values at $45^{\circ}C$ for 25 days. The patterns of these extracts were compared by using high performance liquid chromatography. Ether extracts from Crataegus and Terminalia showed a higher antioxidative effectiveness than BHA and BHT, and the latter was more effective than the former Among phenolic extracts, free phenolic acid and soluble phenolic acid ester were found most effective in Crataegus and Terminalia, respervively, Each phenolic extract was confirmed to be composed of two or three individual compounds.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.241-247
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• 2013

Objectives: The aim of this study was to determine the effect of epigallocatechin gallate (EGCG) on the shear bond strength of composite resin to bleached enamel. Materials and Methods: Ninety enamel surfaces of maxillary incisors were randomly divided into 9 groups as follows: G1: control (no bleaching); G2: bleaching; G3: bleaching and storage for seven days; G4 - 6: bleaching and application of 600, 800 and 1,000 ${\mu}mol$ of EGCG-containing solution for 10 minutes, respectively; G7 - 9: bleaching and application of 600, 800 and 1,000 ${\mu}mol$ of EGCG-containing solution for 20 minutes, respectively. The specimens were bleached with 30% hydrogen peroxide gel and a composite resin cylinder was bonded on each specimen using a bonding agent. Shear bond strength of the samples were measured in MPa. Data was analyzed using the two-way ANOVA and Tukey HSD tests (${\alpha}$ = 0.05). Results: The maximum and minimum mean shear bond strength values were observed in G1 and G2, respectively. Time and concentration of EGCG showed no significant effects on bond strength of the groups (p > 0.05). Multiple comparison of groups did not reveal any significant differences between the groups except for G2 and all the other groups (p < 0.05). Conclusions: There is a significant decrease in bond strength of composite resin to enamel immediately after bleaching. A delay of one week before bonding and the use of EGCG increased bond strength of composite resin to bleached enamel.

• Journal of Nutrition and Health
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• v.40 no.2
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• pp.138-146
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• 2007

Food irradiation has been steadily increased in many countries concomitantly with increasing international trades. Harmful contaminants naturally occurred from foods which contain high levels of unsaturated fatty acids that are easily oxidized can affect the human anti-oxidation system through the generation of free radicals. Moreover, previous studies proved that ${\gamma}$-irradiation may cause production of free radicals in food. We investigated the effect of ${\gamma}$-irradiated soybeans in relation to oxidative stress in mice. Oxidative index of mice was evaluated by TBARS, DNA fragmentation in various organs such as blood lymphocytes, liver and kidney. Forty male ICR mice were equally divided into 4 groups and fed control diet or ${\gamma}$-irradiated diet containing 50% soybeans (5, 10, and 20 kGy, respectively) for 8 weeks. Peroxide values of the irradiated diets were higher than that of the non-irradiated one and increased according to the storage period. There was no significant difference in weight gain as well as in TBARS value in plasma and kidney of all groups. Liver TBARS value of the group fed with irradiated diet at 20 kGy increased significantly compared with the control group (p < 0.05). DNA oxidative damage as measured by alkaline comet assay showed that % tail DNA in the blood lymphocytes of 5 kGy and 10 kGy groups increased significantly over the control group (p < 0.05). Also, tail moments of 5 kGy and 10 kGy groups were higher than that of the control group. Ultrastructural examination shows myeline figures and swollen mitochondria in parietal and intestinal epithelial cells of the group fed with irradiated diet. Therefore, considering unsaturated fatty acid content, consumption of soybeans ${\gamma}$-irradiated with over 20 kGy or repeatedly may decrease the body's antioxidant mechanism.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.535-540
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• 1992

The antioxidant activities of Epimedium koreanum N. methanol extract on the oxidation of fats and oils were studied by measuring peroxide values during storage at $75^{\circ}C$. The methanol extract showed high antioxidant activity on the oxidation of lard and corn oil, and the antioxidant effectiveness increased as the concentrations of the extract in lard increased. After heating the extract at $180^{\circ}C$ for 120 min, the heat-treated extract exhibited above 66% of the original antioxidant effectiveness on the oxidation of lard during storage at $75^{\circ}C$. Epimedium koreanum N. extract, however, accelerated the oxidation of soybean oil during storage under irradiation of ultraviolet light. The main antioxidant components in Epimedium koreanum N. extract seemed to be tocopherols and flavonoids. The contents of ${\alpha}$, ${\beta}$, ${\gamma}$ and ${\delta}-tocopherol$ in the extract were 21.61, 1.48, 5.50 and 3.75 mg%, respectively.

• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.249-257
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• 2016

In this study, rapeseed extracts were obtained by supercritical carbon dioxide fluid extraction of defatted rapeseed to evaluate the stability and antioxidant activity of an oil-in-water (O/W) emulsion system. The oil-in-water emulsions were prepared from stripped soybean oil with different concentrations (0.3, 0.4, 0.5, and 0.6%) of rapeseed extract as an emulsifier. Their emulsion stability was compared to that of emulsions prepared with the commercial emulsifier, Tween 20 (Polysorbate 20, 0.2%). After stripping the soybean oil, the total tocopherol content was reduced from 51.4 g/100 g to 1.1 g/100 g. Emulsion stability and oxidative stability of emulsions prepared with Tween 20 and rapeseed extract as emulsifiers were evaluated. For 30 days droplet sizes of emulsions containing rapeseed extract (0.4, 0.5, and 0.6%) were not significantly different (p > 0.05). Similar results were obtained for emulsion stability (ES) and Turbiscan analysis, suggesting that the addition of rapeseed extract increased emulsion stability. The addition of rapeseed extract at more than 0.4% resulted in an emulsion stability comparable to the addition of 0.2% Tween 20. The antioxidative ability of rapeseed extract increased with the amount added in the emulsion. Moreover, the addition of 0.6% rapeseed extract resulted in the lowest emulsion peroxide values (10.3 mEq/L) among all treatments. Therefore, according to the stability of its antioxidative and physical stability properties, rapeseed extract from super critical extraction could be successfully applied to the food and cosmetic industries.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.693-700
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• 2011

To evaluate the antioxidant effects of vitamin C, vitamin E and sorghum bran, alone or in combination on chicken sausages, 9 kg of chicken thigh meat was prepared. All thigh meat was divided into seven different batches as follows; no antioxidant (CON); vitamin C (VTC), vitamin E (VTE) or sorghum bran (SOR) at 0.02%; or three different combination ratios of vitamin C, vitamin E and sorghum bran at 0.02% (VT2, 2:1:1; VT4, 4:1:1; VT6, 6:1:1). All cooked sausages were stored at $4^{\circ}C$, and six sausages per treatment were used for chemical analysis on five different storage days. As the addition of vitamin E was increased, sausages stored for 10 d had decreased redness; thereby, VTE showed the lowest CIE $a^*$ (p<0.05). Sausages mixed with vitamins and sorghum bran combinations had lower peroxide and free fatty acid values (p<0.05) when compared to sausages without antioxidants. The TBARS were the lowest in sausages containing vitamin C, vitamin E and sorghum bran at 6:1:1 ratio, and they significantly differed to CON, VTC and SOR treatments (p<0.05). Therefore, our results suggest that meat mixed with vitamins and sorghum bran had more antioxidant activity than the meat mixed with only antioxidant vitamins or without antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.901-907
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• 1997

The purpose of this study was to investigate the effects of green tea catechin o n free radical generation system and peroxidative damage in the liver of streptozotocin(STZ)-induced diabetic rats. Spragu-Dawley male rats weighing 150$\pm$10gm were randomly assigned to one normal and three STZ-induced diabetic groups; diabetic groups were classified to catechin free diet(DM-oC group), 0.5% catechin diet(DM-0.5C group) and 1% catechin diet(DM-1C group) according to the levels of dietary catechin supplementation. Diabetes was experimentally induced by intravenous injection of 55mg/kg of body wt of STZ in citrate buffer(pH 4.3) after feeding of three experimental diet for 4 weeks. Animals were sacrificed at the 6th day of diabetic states. Activities of serum glutamic oxaloacetic transaminase(GPT) in DM-oC groups were higher than those of the normal group, and those in catechin supplementation group were similar to those of the normal group. Liver lipid peroxide values increased by 153%, 49%, and 27% in Dm-oC, DM-0.5C and DM-0C and Dm-1C but was not significantly different in catechin supplementation groups compared with the normal group, and liver cytochrome $P_{450}$ contents was similar to result of XOD activity. In electron microscopic examination of liver, lysosome was relatively scattered in Dm-oC and Dm-0.5C group and preserved normal shapes in DM-1C group. The present results indicate that STZ-induced diabetic rats are more sensitive to oxidative stress, leading to the acceleration of lipid peroxidation process, but this was reduced by anti-oxidative effect of high level of dietary catechin. It is concluded that dietary catechin serves as powerful antioxidant against lipid peroxidation in diabetic rats.