• Applied Biological Chemistry
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• v.37 no.3
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• pp.168-174
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• 1994

Effects of filtration and centrifugation on the oxidative stabilities of sesame oils during storage at $70^{\circ}C$ were studied by combination of determining peroxide values and conjugated dienoic acid values of oils and measuring the hexanal formation using headspace gas chromatography. Crude sesame oil from roasted seeds contained more free fatty acids, conjugated dienes, and metals (Fe, Cu, Mg and Zn); on the other hand, higher contents of moisture and ${\gamma}-tocopherol$ were found in the filtered or centrifuged oil. Only filtered oil contained more peroxides than the crude oil in spite of the color advantage of the highest L and b values among three oils. All the oils showed the tendency of increasing in total color difference during storage at $70^{\circ}C$, fatty acid compositions were relatively constant except for decreasing tendency of linoleic acid in filtered oil. No significant difference at 1% in the oxidative stabilities was observed between centrifuged oil and crude oil with higher susceptibility to the oxidation in the filtered oil. Centrifuged sesame oil was the best in the aspect of both oxidative stability and the oil color.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.963-966
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• 2007

The objectives of this study were to identity antioxidant substance in heated garlic juice (HGJ). We evaluated the antioxidant activities of heated garlic juice exposed to 120, 130, and $140^{\circ}C$ for 2 hr. The HGJ was partitioned using the solvents of hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction of HGJ treated at $130^{\circ}C$ for 2 hr showed strong antioxidant activity; this extract was isolated and purified using silica gel column chromatography and semi-preparative high-performance liquid chromatography. The structure of the purified compound was determined using spectroscopic methods, i.e., ultraviolet, mass spectrometry, infrared, $^1H$ NMR, $^{13}C$ NMR, DEPT, HMBC, and HMQC. The isolated compound was identified as thiacremonone (2,4-dihydroxy-2,5-dimethyl-thiophene-3-one). Thiacremonone showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, with a 50% inhibition concentration ($IC_{50}$) of $22.25{\pm}0.44\;{\mu}g/mL$, which is much higher than that of the antioxidants ascorbic acid ($30.06{\pm}0.42\;{\mu}g/mL$), ${\alpha}$-tocopherol ($71.30{\pm}0.97\;{\mu}g/mL$), and butylated hydroxyanisole ($50.54{\pm}0.94\;{\mu}g/mL$).

• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.409-412
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• 2015

Changes in the contents of mevinolins (natural statins, $0-568.18{\mu}g$), coenzyme Q10 (CoQ10, $26.41-65.59{\mu}g$), and tocopherols ($232.80-312.87{\mu}g/g$ dry weight) in Monascus-fermented soybean were determined using HPLC. Significant increases (p<0.05) in mevinolins and CoQ10 were obtained in Monascus-fermented soybean after 20 days of fermentation compared with unfermented soybean (0 days), whereas no significant change (p>0.05), or a slight decrease, in tocopherols was observed. The results indicate that Monascus-fermentation has great potential for enriching mevinolin and CoQ10 in soybeans.

• Journal of Life Science
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• v.6 no.1
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• pp.66-71
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• 1996

Antioxidative activity of various solvent extracts from freeze dried Kimchi was studied during the oxidation process of linoleic acid mixture system. The aqueous model systems were used for the evaluation of antioxidative activity of solvent extracts during the oxidative reaction at 37$^{\circ}C$ by the determination of peroxide value. The linoleic acid mixture for the aqueous model systems was consisted of linoleic acid (64.6%), oleic acid(27.4%), and other acids in ethanolic phosphate buffer (pH 7.0). Water and methanol extracts of Kimchi had a considerable antioxidative activity with the inhibition of peroxides formation during the autoxidation of linoleic acid mixture in aqueous model systems. Antioxidative activity of 75% methanol extract of 7 day-fermented-Kimchi was relatively higher than that of others, however lower than alpa-tocopherol and butylated hydroxyanisol. The antioxidative effect of 75% methanol extract of 7 day-fermented-Kimchi was increased by the its concentration from 0.5% to 2.5% in the oxidation reactions of aqueous model systems.

• Korean journal of food and cookery science
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• v.33 no.1
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• pp.113-120
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• 2017

Purpose: Lipid autoxidation of a soybean oil-in-water emulsion with high oil content was studied under after basil extract and/or iron addition. Methods: The emulsion consisted of tocopherol-stripped soybean oil (40 g), citrate buffer (60 g, pH 4.0), and/or $FeSO_4$ (0.5 mg) with 75% ethanol extract (200 mg/kg) of basil (Ocimum basilicum). Lipid oxidation was evaluated using headspace oxygen content, hydroperoxide contents, and p-anisidne values of the emulsion. Polyphenol compound retention in the emulsion during oxidation was determined spectrophotometrically. Results: Addition of basil extract significantly (p<0.05) decreased reduced hydroperoxide contents of the emulsion, and iron significantly (p<0.05) increased anisidine values and decreased oxygen contents. Co-addition of basil extract and iron showed significantly (p<0.05) lower reduced hydroperoxide contents in the emulsion than compared to those of the emulsion with added iron and the control emulsion without basil extract nor or iron. During the emulsion oxidation, polyphenol compounds in the emulsion with added basil extract were degraded, but more slowlywhich was slowed degraded in the presence of iron. Conclusion: The iIron increased the lipid oxidation through hydroperoxide decomposition, and basil extract showed antioxidant activity through radical-scavenging and iron-chelation. Polyphenol degradation was decelerated by iron addition, which suggested suggests iron chelation may be more preferred topreferentially activated over radical scavenging in the antioxidant action by of basil extract in the oil-in-water emulsion with high oil content.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.226.2-227
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• 2003

The degree of milling is an important factor in terms of the nutritional value and the economic return of the milled rice. This study was to investigate the changes in compositions of the oils obtained from rice with different degree of milling. The content of total tocols in rice significantly (p＜0.05) decreased, as degree of milling increased. The relative ％ of -tocopherol in brown rice had lower than those in milled rices whereas the relative ％ of -tocotrienol, and -tocotrienol in brown rice higher than those in milled rices. -Oryzanol content significantly (P<0.05) decreased from 198.5 mg/kg rice for brown rice (0% milling) to 65.5 125.0 mg/kg rice for rice samples with 5.6, 8.0, and 9.6 ％ milling. -Sitosterol was most abundant sterol representing 50 ％ - 56% of the total sterol content in all analyzed samples. The content of total sterol as well as each sterol isomers in rice significantly (P<0.05) decreased, as degree of milling increased. A similar trend was observed in changes of octacosanol and squalene.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.595-600
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• 1997

The antioxidant activity of the solvent fractions extracted from onion skin was examined. The antioxidant activity of methanol extract at the cencentration of 0.02% and 0.03% was stronger than that of mixed tocopherol. The antioxidant activity of the fractions of methanol extract increased in the order of butanol> ethyl acetate> ethyl ether> water fraction. The antioxidant activity of each fractions was strongly related with total phenol content and HDA. Further separation of butanol fraction by TLC yielded 6 fluorescent bands with Rf values of 0.20, 0.33, 0.49, 0.60 and 0.94. The total phenol content and HDA of fluorescent band, Rf 0.96, were remarkable higher than those of the other band and exhibited a strong UV absorption at 255 nm and 317 nm, which would be specifically produced by flavonol. Spectral analyses indicated that the major antioxidant component was quercetin aglycone (3,3',4',5,7-pentahydroxyflavone).

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.924-933
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• 1999

This study investigated the effects of vitamin E supplementation on immune responses and antioxidant status in healthy Korean old and young women. Blood samples were obtained from 15 healthy old women (over 60 years old) and from 15 healthy young women(20 years old) before and 4 weeks after vitamin E( tocopherol acetate) supplementation(400IU/day). Daily nutrient intakes were calculated, and plasma vitamin E concentration, numbers and percentages of white blood cell and their subpopulation, percentages of lymphocytes and subpopulation, NK cell percentages, plasma immunoglobulin A, G, M and C3 concentration, proliferation of PMN with mitogen were measured. Also plasma TBARS concentration and radical scavenger activity of erythrocytes were investigated. Plasma vitamin E concentrations were significantly increased after supplementation in both groups. In elderly women, vitamin E supplementation restored the per centages of neutrophils, lymphocytes, and eosinophils which had been out of normal ranges before supple mentation. And after vitamin E supplementation, helper T cell percentages significantly increased in elderly. Plasma immunoglobulin and complement C3 concentrations were not affected by vitamin E supplementation in both groups. PMN proliferations with mitogen were significantly lower in old women than in young women, and there was no effect of vitamin E supplementation. Vitamin E supplementation significantly decreased plasma TBARS concentrations in old and young women. RSA of erythrocytes was increased in both groups, but the statistical significant was only found in young women group. Therefore, these results suggest that the moderate vitamin E supplementation in old women improves immune responses, especially nonspecific immunity and cell mediated immunity, via protection of oxidant stress.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.766-770
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• 2009

Hot water extracts of Camellia japonica flower buds were found to have the higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the other solvent extracts. Five phenolic compounds were isolated and purified from the ethyl acetate soluble-neutral fraction of hot water extracts by Sephadex LH-20 column chromatography and octadecyl silane-high performance liquid chromatography using the guided assay of DPPH radical scavenging. Based on mass spectrometer and nuclear magnetic resonance, the isolated compounds were identified as p-hydroxybenzaldehyde (1), vanillin (2), dehydroxysynapyl alcohol (3), 7S,7'S,8R,8'R-icariol $A_2$ (4), and (-)-epicatechin (5). Four compounds (1-4) except for 5 were newly identified in this plant. Their DPPH radical scavenging activities as 50% scavenging concentration decreased in order to 5 $(20\;{\mu}M)>{\alpha}-tocopherol$ $(29\;{\mu}M)>4$ $(67\;{\mu}M)>3$ $(72\;{\mu}M)>1=2$ ($>250\;{\mu}M$). These results indicate that the antioxidant effect of the hot water extract of C. japonica flower buds may partially due to 5 isolated phenolic compounds.

• Korean Journal of Medicinal Crop Science
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• v.19 no.4
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• pp.251-256
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• 2011

The leaves of Hippophae rhamnoides were extracted with methanol and then further fractioned with hexane, ethyl acetate, butanol and water in order to investigate biological activity. Two flavonol glycosides were isolated and identified from ethyl acetate soluble fraction, which showed the strongest antioxidant activity ($RC_{50}$ = 4.33 ${\mu}g/ml$). Isolated two compounds have shown strong free radical scavenging activity. Especially, quercetin 3-O-glucoside ($RC_{50}$ = 2.60 ${\mu}g/ml$) was more active than ${\alpha}$-tocopherol ($RC_{50}$ = 4.67 ${\mu}g/ml$). Total phenol and flavonoid contents were the highest to 4.17 and 1.14 mg/ml in the ethyl acetate soluble fraction. In addition, ethyl acetate soluble fraction was shown to the strongest ${\alpha}$-glucosidase inhibitory activity ($IC_{50}$ = 137.88 ${\mu}g/ml$) among the fractions. The results suggest that leaves of H. rhamnoides could be a potential source of natural antioxidant.