• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.43-48
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• 2009

Current study investigated phytochemical compositions and antioxidant capacity of Korean leafy vegetables including chajogi, gomchwi, meowi and sseumbagwi. ${\beta}$-carotene, total soluble polyphenol, total flavonoids contents were determined, and antioxidant capacity were evaluated by various methods. ${\beta}$-carotene, total soluble polyphenol, total flavonoids contents in gomchwi were significantly higher (as much as 19 folds) compare to other vegetables (p<0.05). Sseumbagwi extract ($100{\mu}g/mL$) was removed 78.6% of superoxide radicals in xanthin-xanthin oxidase system measured by EPR. Gomchwi showed the highest nitrate scavenging activity as 94.3% at pH 1.2. In SOD-like activity, chajogi, gomchwi, and meowi were evaluated in the range of $12.6{\sim}24.5%$. All samples were revealed to prevent the reaction of ferrous chloride during 9 days, which were comparable ability with 125 mg/100 g of ${\alpha}$-tocopherol. The rich phytochemical contents of gomchwi and sseumbagwi influenced to high antioxidant capacity.

• Journal of Ginseng Research
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• v.33 no.1
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• pp.40-47
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• 2009

This study evaluates changes in the chemical composition and bioactivities of American ginseng (Panax quinquefolius L.) processed by boiling in water, $75^{\circ}C$ for 10, 20, 30, and 40 min, and autoclaving at high temperatures, $115^{\circ}C$ for 30 and 60 min and $130^{\circ}C$ for 90 and 120 min. Total ginsenoside contents of boiled ginseng remained relatively unchanged, whereas the contents of autoclaved ginseng samples significantly decreased with an increase of both time and temperature. Compared to unheated ginseng (control), the color of both boiled and autoclaved ginseng decreased in lightness and increased in redness. The acidic polysaccharide contents, the total phenolic contents and the antioxidant capacity of boiled and autoclaved ginseng were higher than the untreated ginseng, with the highest values being exhibited by the autoclaved samples. In particular, the antioxidant capacity of unheated ginseng increased about 2.5 times ($285.7{\pm}14.03\;mg$/100g to $777.2{\pm}26.4\;mg$/100g) when ginseng was autoclaved at $130^{\circ}C$ for 120 min as compared to the control. It was concluded that as American ginseng was processed at a high temperature, especially steam-heated in an autoclave, its chemical constituents changed and, in particular, acidic polysaccharides, total phenolics and antioxidant capacity were considerably increased.

• Journal of fish pathology
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• v.24 no.2
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• pp.141-152
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• 2011

Growth, oxidative stress and antioxidant capacity of Fucus serratus exposed to high doses of Cd were examined. Two sites in Southwest England (Restronguet Point and Bantham Quay) were selected since they had different histories of metal contamination. 1~10 mg Cd $L^{-1}$ were treated to Aquil medium for up to 14 days. Similar levels of lipid peroxidation but different values of relative growth rates, cupric ion reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity indicated that F. serratus has population-dependent antioxidant strategies. F. serratus demonstrated cadmium resistance with no visual symptoms for 14 days and the population from the polluted area seemed to have more powerful antioxidant strategies. However Fucus from the conserved area also showed protective anti oxidative mechanism.

• Korean Journal of Medicinal Crop Science
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• v.24 no.5
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• pp.351-359
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• 2016

Background: We investigated the optimal aqueous extraction conditions for recovery of high yields of total phenolic compounds from roots of Arctium lappa L. (burdock, Asteraceae), and we compared their antioxidant capacity. Methods and Results: The antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, and oxygen radical absorbance capacity assays. In addition, the major phenolic compounds present in the extracts were determined by high performance liquid chromatography analysis. Our results suggest that the roasted burdock $100^{\circ}C$, 15 min extract exhibited the strongest radical scavenging activity and possessed the highest concentration of phenolic compounds. The polyphenol content of both dried burdock and roasted burdock significantly increased with increase in the extraction temperature and time. Conclusions: These results indicated a relationship between phenolic compound levels in burdock and their free radical scavenging activities. This suggests that phenolic compounds significantly increase the antioxidant potential of burdock extracts.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.222-227
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• 2008

The objective of this study was to evaluate the antioxidant activity of yuza chocolate,and to determine the optimum ratio of yuza powder for its preparation. Yuza peel and flesh powders were added to chocolate at weight percentages of 0, 3, and 6%, respectively. Color values (L-value, redness, and yellowness), total phenol content, total antioxidant capacity, DPPH radical scavenging activity, and sensory characteristics were then measured in the samples of yuza-containing chocolate. As the amount of yuza powder increased, total phenol content, antioxidant capacity, and radical scavenging activity increased. Depending on the level of yuza powder, significant differences (p <0.05) were shown in aroma, taste, bitterness, and overall acceptability however, there were no significant differences in texture. In terms of sensory acceptability, the addition of 3% yuza peel powder to chocolate was optimal.

• Journal of Forest and Environmental Science
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• v.37 no.3
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• pp.226-234
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• 2021

Two species, P. pyrifolia and P. ussuriensis, of the genus Pyrus native to Korea, are valuable genetic resources that can be used for food, dietary supplement, pharmaceutical, and cosmetics. Bioactive compounds of the plant leaves are the main components that are used for the products. Farmers had cultivated a few individuals from the wild to produce fruits or leaves for traditional remedy or tea; however, bioactive components of their leaves are not tested. We selected some trees from the natural stand that have distinct traits for the improvement program. We investigated the bioassay on the extracts' bioactive compounds and antioxidant capacity from the selected accessions and other accessions, including newly developed cultivars. The contents of the phenolic compounds and flavonoids from the leaf extracts of the selected accessions were higher than the commonly cultivated trees in both species but lower than 'Sanhyang' in P. ussuriensis. The antioxidant capacity was measured using two assay methods, DPPH and ABST. The selected cultivars also had higher inhibitory activity than common trees. The selected accession 'Cultivar 3' in P. pyrifolia had the highest radical scavenging activity than others. Although leaves of the accessions were used only in this study, all three selected individuals have the potential for cultivar in containing high bioactive compounds and antioxidant capacity.

• Food Science and Preservation
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• v.30 no.2
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• pp.300-310
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• 2023

This study was carried out to investigate the effect of the extraction conditions for persimmon (Diospyros kaki Thunb.) leaf tea (PLT) on its color quality and antioxidant properties. The amount of persimmon leaf (PL) powder and pH influenced the PLT's color and antioxidant capacity. As the amount of PL powder in tea increased, lightness decreased while yellowness increased. The PLT with the highest amount of PL (10 mg/mL) exhibited the highest 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity and ferric reducing antioxidant power (FRAP). In addition, the PLT with the highest PL showed the highest total polyphenol and flavonoid contents. Subsequently, PLT was prepared using 10 mg/mL PL powder under varying pH conditions. As pH increased from 4 to 7, lightness decreased while redness and yellowness increased. Antioxidant capacity was determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and FRAP assay showed that lower pH exhibited higher antioxidant capacity. The PLT extracted under the lowest pH of 4 showed higher polyphenol and flavonoid contents than that extracted under higher pH conditions. Overall, PLT extraction using a solvent with pH 4.0 showed better antioxidant activities and higher amounts of polyphenolic compounds. Simultaneously, lesser lightness, redness, and yellowness were detected in PLT extracted under pH 4 conditions. In conclusion, to acquire a better functional health benefit in terms of antioxidant capacity, preparing PLT under pH 4 conditions is suggested.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.412-420
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• 2016

The objective of this study was to investigate characteristics and functionality of yogurt applied red ginseng extract. Yogurts added with red ginseng extract (0.5, 1, 1.5, and 2%) were produced using Lactobacillus acidophilus and Streptococcus thermophilus and stored at refrigerated temperature. During fermentation, pH was decreased whereas titratable aicidity and viable cell counts of L. acidophilus and S. thermophilus were increased. The composition of yogurt samples was measured on day 1, an increase of red ginseng extract content in yogurt resulted in an increase in lactose, protein, total solids, and ash content, whereas fat and moisture content decreased. The pH value and cell counts of L. acidophilus and S. thermophilus were declined, however titratable acidity was increased during storage period. The antioxidant capacity was measured as diverse methods. During refrigerated storage time, the value of antioxidant effect was decreased, however, yogurt fortified with red ginseng extract had higher capacity than plain yogurt. The antioxidant effect was improved in proportion to concentration of red ginseng extract. These data suggests that red ginseng extract could affect to reduce fermentation time of yogurt and enhance antioxidant capacity.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1464-1469
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• 2009

Jiwhang (Rehmannia glutinosa), one of the most widely used medicinal herbs, was dried with various methods such as sun drying, hot air drying, vacuum drying, and freeze drying methods, and their effects on the antioxidant capacity in relation with the content of total phenolic compounds were studied with a steamed-and-dried rehmannia (sookjiwhang) for comparison. Generally, total phenolic contents decreased significantly by all of the drying treatments except the steamed-and-dried rehmannia, in which total phenolic contents increased 2.4 fold compared with fresh rehmannia. Content of verbascoside, a functional phenolic compound, was the highest in the freeze-dried rehmannia ($177.97{\pm}0.02\;{\mu}g/g$ d.m.) followed by vacuum-dried ($105.55{\pm}0.07\;{\mu}g/g$ d.m.), hot air-dried ($23.01{\pm}0.02\;{\mu}g/g$ d.m.), and sun-dried ($4.89{\pm}0.13\;{\mu}g/g$ d.m.) ones comparable to the fresh rehmannia ($80.15{\pm}1.26\;{\mu}g/g$ d.m.). Antioxidant capacity determined by both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) methods agreed with the result of total phenolic contents, that is, the antioxidant capacity was the highest in the steamed-and-dried rehmannia followed by fresh rehmannia, vacuum-dried, hot air-dried, sun-dried, and freeze-dried ones. Conclusively, the total phenolic contents and antioxidant capacity of rehmannia were greatly affected by the drying methods used.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.388-394
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• 2017

Although several analytical methods for measuring total antioxidant capacity (TAC) have been applied to biological samples, there were often dissimilar results due to the different principles of methods applied. Thus, this study aimed to validate four conventional analytical methods for measuring plasma TAC, including the ABTS assay, DPPH assay, FRAP assay, and ORAC assay, by comparing with urinary 8-isoprostane concentration. In addition, TAC results were compared with antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase in erythrocyte, and catalase in plasma. Plasma TAC measure by ABTS assay was strongly correlated with the result by FRAP assay. Plasma TAC by FRAP and ORAC assays were negatively correlated with erythrocyte SOD activity. The agreement among the four TAC assay methods and 8-isoprostane was determined using 95% prediction limits of linear regression, expressed as the mean of 8-isoprostane ${\pm}95%$ prediction limits. The ABTS method better agreed with 8-isoprostane than the other methods, demonstrating narrow prediction of limits. Furthermore, only plasma TAC determined by the ABTS assay was inversely correlated with urinary 8-isoprostane (r = -0.35, p < 0.05). In summary, the ABTS assay would be an appropriate method to measure overall plasma antioxidant capacity and predict the body's antioxidant status.