• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1214-1220
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• 2016

This study compared antioxidant compounds and antioxidant activities according to various varieties of 18 colored rice. Selected rice cultivars for this study were as follows: black rice (12 cultivars)-Heugjinjubyeo, Nunkeunheugchal, Joeunheugmi, Josaengheugchal, Heuggwang, Heugseol, Shinmyeongheugchal, Shinongheugchal, Shintoheugmi, Cheongpungheukchal, Heughyang, Boseogheugchal, red rice (four cultivars)-Jeogjinju, Jeogjinjuchal, Hongjinju, Geonganghongmi, and green rice (two cultivars)-Nogwonchal and Jungmo1020. These were transplanted on June 30th and cultivated from the Department of Southern Area Crop Science, National Institute of Crop Science in Miryang, Korea. Total polyphenol (TP) content of black rice cultivars was higher than that of red rice varieties. Heugjinjubyeo exhibited the highest TP, which was $9.55{\pm}0.05mg$ gallic acid equivalent/g sample. There were no significant differences between black rice cultivars and red rice cultivars in terms of total flavonoid (TF) level. Heugjinjubyeo and Hongjinju showed the higher TF content than any other variety. Shintoheugmi revealed the highest anthocyanin content ($194.26{\pm}0.65mg/100g$). Methanol extract of Heugjinjubyeo had the highest antioxidant activities. 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities of Heugjinjubyeo extract were $14.70{\pm}0.62$ and $30.68{\pm}2.22{\mu}g/mL$, respectively. There were significant correlations between antioxidant compound content and antioxidant activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.302-309
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• 2012

Effects of cultivation time on the antioxidant contents and activities of foxtail millet and proso millet were determined. The cultivation times were early-season (ES), normal-season (NS), and late-season (LS), and the cultivated varieties were Hwanggeum-cho (HGC), Cheongcha-cho (CCC), Samdamae (SDM), Gyeongkwan 1 (GK 1), Gyeongkwan 2 (GK 2), Ganghae-cho (GHC), Hwanggeum-gijang (HGG), Manhongchal-gijang (MHCG), Byeoruk-gijang (BRG), Norangchal-gijang (NRG), and Whin-gijang (WG). The total polyphenol, flavonoid, tannin content, and DPPH and ABTS radical scavenging activities of the methanolic extracts of foxtail millet and proso millet showed significant differences according to cultivation variety and time. The highest total polyphenol content of foxtail millet was 29.33 mg of gallic acid equivalent (GAE)/g of sample in GK 1 at LS, whereas that of proso millet was 23.48 mg of GAE/g of sample in BRG at LS. The highest total flavonoid content of foxtail millet was 2.12 mg of catechin equivalent (CE)/g of sample in CCC at ES, whereas that of proso millet was 4.49 mg of CE/g of sample in BRG at LS. The highest total tannin content of foxtail millet was 14.07 mg of tannic acid equivalent (TAE)/g of sample in SDM at LS, whereas that of proso millet was 15.59 mg of TAE/g of sample in BRG at LS. The highest DPPH radical scavenging activity of foxtail millet was 7.71 mg of TE/g of sample in CCC at NS, whereas that of proso millet was 12.66 mg of TE/g of sample in BRG at LS. The highest ABTS radical scavenging activity of foxtail millet was 8.05 mg of TE/g of sample in GK 1 at LS, whereas that of proso millet was 34.46 mg of TE/g of sample in BRG at LS. Generally, HGC, GK 1, and GHC had more beneficial effects at LS than ES or NS, whereas CCC, SDM, and GK 2 had more beneficial effects at NS than ES or LS, and proso millet had more beneficial effects at LS than ES or NS.

• Journal of Life Science
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• v.25 no.4
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• pp.433-440
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• 2015

Several studies suggest that regular consumption of walnuts may have beneficial effects against oxidative stress-mediated disease such as cancer. The present study reports the total phenolic and flavonoid contents, together with the antioxidant and antibacterial activities of several solvent extracts (methanol, n-hexane, ethyl acetate, n-butanol, and water) obtained from walnut (Juglans regia L.) green husk. MIC (minimal inhibitory concentration) values of the walnut extracts for 8 human pathogenic bacteria strain were determined using agar dilution method. Antioxidant activity of extracts were assessed using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) assays, EC₅₀ of DPPH and ABTS scavenging activities, and determination of total phenolic and flavonoid content and its correlation with DPPH and ABTS scavenging capacities. Among the six extracts, ethyl acetate extract (EtOAc Ex) showed the highest antimicrobial activity at 3.2 mg/ml of MICs against Staphylococcus aureus SG511. Total flavonoids and polyphenol contents of EtOAc Ex were 42.48 mg of quercetin equivalents (QE)/g and 223.25 mg of gallic acid equivalents (GAE)/g respectively. The highest antioxidative potential was shown by the sample extracted with EtOAc Ex (EC₅₀=13.43 μg/ml for DPPH and EC₅₀=41.83 μg/ml for ABTS radical scavenging activity assay). These results showed that J. regia green husk extracts can be used as an easily accessible source of natural antibacterial agents and natural antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1316-1326
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• 2017

We evaluated the proximate compositions of raw materials, total polyphenols, total flavonoids, and radical scavenging activities of roasted maize tea according to cultivation period and variety. Proximate compositions of raw materials were significantly different according to cultivation period and variety, and quality characteristics of roasted maize tea extracts were significantly different according to cultivation period. Total polyphenols, total flavonoids, and radical scavenging activities of roasted maize tea were significantly different before and after roasting. The total polyphenol content of Pyeonggangok cultivar sown on April 5th was elevated about 3.60-fold before and after roasting by $3.42{\pm}0.16$ and $12.22{\pm}0.67mg$ gallic acid equivalents/g, respectively. Overall, total polyphenol content was higher in roasted maize tea produced using maize sown on April 5th. 1,1-Diphenyl-2-picrylhydrazyl radical scavenging activity of Gangdaok cultivar sown on April 5th was elevated about 31.6-fold before and after roasting by $7.61{\pm}1.93$ and $240.37{\pm}8.82mg$ Trolox equivalents (TE)/g, respectively. 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activity of Pyeonggangok cultivar sown on April 5th was elevated about 5.5-fold before and after roasting by $153.84{\pm}1.32$ and $843.54{\pm}3.64mg$ TE/g, respectively. The correlation between proximate compositions of raw materials and quality as well as antioxidant characteristics of roasted maize tea showed overall significance.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.4
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• pp.352-360
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• 2017

This study evaluated the quality characteristics, polyphenolic compounds, and radical scavenging activity of cooked-rice added to commercially available mixed grains. L-value of cooked-rice with various mixed grains decreased compared to that of cooked-white rice; however, a- and b-values increased. Hardness and elasticity of cooked-rice added to various mixed grains were significantly lower in the pressure cooker compared to the electric cooker. There was no significant difference in adhesiveness and stickiness between rice from the electric cooker and pressure cooker. Total polyphenol and flavonoid contents of cooked-rice added to various mixed grains were significantly increased. The average total polyphenol content of cooked-rice added to various mixed grains cooked in an electric cooker and pressure cooker were $16.50{\pm}3.86$ and $15.88{\pm}3.52mg$ gallic acid equivalent /100 g, and flavonoid contents were $1.58{\pm}0.00$ and $1.55{\pm}0.02mg$ catechin equivalents/100 g, respectively. The average of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity was $9.27{\pm}2.62$ and $8.72{\pm}2.41mg$ trolox equivalent (TE)/100 g, and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was $22.89{\pm}4.60$ and $23.07{\pm}4.49mg$ TE/100 g for cooked-rice added to various mixed grains cooked in an electric cooker and pressure cooker, respectively. Phenol content and radical scavenging activity of cooked rice was in proportion to the amount of added grains, such as brown rice, colored rice, barley, soybean, and sorghum.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.430-437
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• 2017

The protective effect of Pteridium aquilinum on high glucose-induced cytotoxicity was examined in vitro to investigate the relationship between diabetic condition and neuronal dysfunction. The ethyl acetate fraction of P. aquilinum (EFPA), with total phenolic content of 265.08 mg gallic acid equivalent/g, showed higher 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)/2,2-diphenyl-1-picrylhydrazyl radical scavenging activities and lipid peroxidation inhibitory effect than any other fraction. In addition, EFPA showed a significant reduction in the inhibitory effect on ${\alpha}$-glucosidase activity ($IC_{50}$ value=$205.26{\mu}g/mL$) compared to the acarbose positive control. The anti-oxidative effect in PC12 cells, protective effects on high glucose-induced oxidative stress in neuronal cells, and neurotoxicity were measured using 2',7'-dichlorofluorescin diacetate, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide, and lactate dehydrogenase assays, respectively. EFPA showed conspicuous inhibitory effect on cellular reactive oxygen species production and neuronal cell apoptosis. Finally, kaempferol-3-glucoside was identified as the main phenolic compound of EFPA using high performance liquid chromatography.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.626-632
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• 2001

The plant extracted from Nameko, Gallic, Green tea, Allspice, Polygonum multiflorum, Schizandra chinensis, Armeniacae and Pine needle were utilized to investigate the effects of extracts on free radical reaction, lipid oxidation and nitrite scavenging ability. The pH of ethanol extracts showed a higher than that of hot water extracts, among of which were showed the lowest pH 3.0 in Schizandra chinensis. The important factor of lipid oxidation were $Fe^{2+}$ ion and active oxygen, in which were bound by plant extracts in case of $Fe^{2+}$ ion existed. However, the hydroxyl radical scavenging ability of extracts were lowed, compared to extracts reacted with $Fe^{2+}$ ion. Among of them, the hydroxyl radical scavenging ability of Nameko and Pine needle extracts had a lower TBARS value than those of control. The iron content of extracts were less than 2.0 mg/100 g, but the total iron content of Schizandra chinensis extracts were 6.8 mg/100 g. The ethanol extracts of pine needle were higher than those of hot water extracts on the basis of $Fe^{2+}$ ion content. The ascorbic acid content of green tea showed 14.3 mg/100 g in hot water extracts and 16.7 mg/100 g in ethanol extracts. Electron donating ability of extracts showed more than 50%, except Nameko and allspices, which were higher in ethanol extracts than those of hot water extracts. The superoxide dismutase(SOD)-like activity of green tea showed 85.3% and 63.5% in hot water and ethanol extracts, respectively. The nitrite scavenging ability of green tea was the most effective in both extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1286-1290
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• 2006

The objectives of this study were to determine antioxidant activities and antioxidnat compounds of 13 imported and 4 domestic red wines and to investigate relationships between antioxidant activities and antioxidant compounds in the selected red wines. The concentrations of total polyphenolics and anthocyanins in the samples were investigated by spectrophotometric methods. ABTS (2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, and reducing power have been used to compare the relative antioxidant activities of the selected red wines. In this study, total polyphenolic contents of the red wines were ranged from 250 to 2,298 mg gallic acid equivalents/L and the anthocyanin contents were ranged from 11 to 349 mg cyanidin-3-glucoside equivalents/L, respectively. As expected, all the red wines exhibited excellent antioxidnat activities (ABTS and DPPH radical scavenging and reducing power) except three domestic red wines. The correlation coefficient between total polyphenolic content and their antioxidant activities, namely ABTS radical scavenging activity, DPPH radical scavenging activity and reducing power, were 0.9784, 0.9905 and 0.8580, respectively. No correlation was observed between total anthocyanin content and their antioxidant activities.

• Journal of Life Science
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• v.31 no.6
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• pp.543-549
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• 2021

Approximately 10% of all angiosperms belong to the Asteraceae family. Plant species belonging to this family have traditionally been used as medicinal plants in the Korean Peninsula. We investigated the antioxidant activity of seed extracts from 14 species belonging to the Asteraceae family. Seeds with ≥ 90% percentage of filled seed and ≥ 50% final germination were used. The total phenolic content was the highest in Dendranthema zawadskii var. tenuisectum (13.5 mg of gallic acid equivalents (GAEs)/g seeds), followed by Dendranthema zawadskii var. latilobum (11.8 mg of GAEs/g seeds), and Callistephus chinensis (11.0 mg of GAEs/g seeds). The total flavonoid content was highest in C. chinensis (9.8 mg of quercetin equivalents (QEs)/g seeds), followed by D. zawadskii var. tenuisectum (7.2 mg of QEs/g seeds) and Taraxacum officinale (6.3 mg of QEs/g seeds). Our results showed that 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity was highest in D. zawadskii var. tenuisectum (57.4 ㎍/ml), followed by T. officinale (59.1 ㎍/ml) and D. zawadskii var. latilobum (65.0 ㎍/ml), with a half maximal inhibitory concentration (IC₅₀) of DPPH scavenging activity. Furthermore, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity was highest in C. chinensis (26.2 ㎍/ml), followed by D. zawadskii var. tenuisectum (38.4 ㎍/ml), T. officinale (40.2 ㎍/ml), with a half maximal inhibitory concentration (IC₅₀) of ABTS scavenging activity. Based on a cluster analysis according to the antioxidant activity, the 14 species were classified into five groups, with group 4 having the highest antioxidant activity and group 0 having the lowest antioxidant activity. D. zawadskii var. latilobum, D. zawadskii var. tenuisectum, T. officinale, and C. chinensis belonging to groups 3 and 4, exhibited high phenolic content and antioxidant activity and can be considered potent plant-derived natural antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.579-585
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• 2015

The objective of this study was to investigate the quality characteristics of coffee soaked in Morus bombycis extract. Green coffee beans were soaked in M. bombycis extract for 2, 4, and 6 hours (sample codes: 2H, 4H, and 6H) at $4^{\circ}C$. Soaked green beans were dried and roasted for coffee extraction. Two controls, roasted with the same amount of heat (C1) and showed the same weight after roasting (C2), were used. Physicochemical characteristics (pH, total acidity, color, browning index, and total soluble solids), DPPH free radical scavenging activity (DPPH), ferric-reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total polyphenol content (TPC), and total flavonoid content (TFC) were investigated. Lower pH and higher total acidity were observed in 2H, 4H, and 6H (P<0.05), supporting evidence of sour taste. There were significant differences in DPPH between the controls (45.51~47.02%) and samples (50.67~55.25%, P<0.05), although 2H and 6H did not show significantly higher DPPH than the controls. 2H, 4H, and 6H showed significantly higher FRAP values ($0.320{\sim}0.331\;FeSO_4{\cdot}7H_2O\;mM\;FeSO_4/g$) than controls ($0.265{\sim}0.271\;mM\;FeSO_4/g$). ORAC values of samples [1,062.86~1,153.68 mM trolox equivalent (TE)/g] were significantly higher than those of controls (689.40~942.12 mM TE/g). 2H, 4H, and 6H showed significantly higher TPC [24.27~26.07 mg gallic acid equivalent (GAE)/g] and TFC [3.75~4.28 mg quercetin equivalent (QE)/g] than controls (19.79~22.77 mg GAE/g and 1.07~1.95 mg QE/g, respectively) (P<0.05). M. bombycis extracts soaked into green coffee beans showed polyphenol compounds from green coffee beans. Consumer acceptance of 4H (5.12) was the highest, followed by C2 (4.92). C1 (4.14) showed the lowest consumer acceptance. Consumers were segmented into two groups, those who preferred M. bombycis extract-soaked coffee (approximately 61%) and controls (approximately 39%).