• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.695-701
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• 2015

This study was conducted to evaluate the effects of drying and extraction methods on antioxidant activity and total phenol content of Gnaphalium affine D. DON (GA). Hot-air, shade-drying, and freeze-drying were used for drying, after which magnetic stirring and ultrasonification were applied. Extracting solvents were water, 80% ethanol, and 80% methanol. Total phenol content was highest in 80% ethanol extract of freeze-dried and stirred GA. Total flavonoid content was highest in 80% methanol extract of freeze-dried and stirred GA. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was higher in 80% methanol and 80% ethanol extracts than in water extract. 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was highest in 80% ethanol extract of shade-dried and ultrasonicated GA. Reducing power was generally higher in 80% methanol extract than in 80% ethanol and water extracts of GA. Total phenol and total flavonoid contents were highly correlated with DPPH radical scavenging activity and reducing power, respectively. This result implies that the antioxidant activity of GA can be attributed to phenol compounds such as flavonoids. Conclusively, phenol compounds such as flavonoids are responsible for the antioxidant activity of GA, and there was no significant effect of drying and stirring conditions on antioxidant activity of 80% ethanol. Meanwhile, DPPH radical scavenging activity of water extract and reducing power of 80% methanol extract were higher in hot-air and shade-dried GAs than in freeze-dried GA.

• The Korean Journal of Food And Nutrition
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• v.33 no.1
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• pp.64-73
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• 2020

The purpose of this study was to investigate the antioxidant activity and β-glucan content of extracts extracted by varying the temperature at 30, 55 and 80℃ after hot air drying or freeze drying of Pleurotus ostreatus and Pleurotus eryngii. For the analysis antioxidant activity of each mushroom, β-glucan, total phenol, flavonoid contents, and DPPH·ABTS⁺·Nitrite assay were measured. Also, the β-glucan content, total flavonoid content and ABTS⁺ scavenging activity increased with freeze drying rather than hot air drying, and increased with increasing extraction temperature in both mushrooms. However, the total phenol and nitrite scavenging activity increased with hot air drying rather than freeze drying, and decreased with increasing temperature in both mushrooms. DPPH scavenging activity was not significant in both mushrooms, but decreased with increasing extraction temperature. Pearson's correlations between total flavonoid content and antioxidant activities were r=0.719~0.753 (p<0.01). As a result, the β-glucan content, total flavonoid content, and ABTS radical cation scavenging activity were highest during freeze drying and extraction at 80℃. And the highest total phenol content, DPPH radical scavenging activity and nitrite scavenging activity were obtained during hot air drying and extraction at 30℃.

• 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 the Korean Applied Science and Technology
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• v.32 no.3
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• pp.418-426
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• 2015

Total phenol contents, total flavonoid contents and antioxidant activity of 70% methanol, 70% ethanol and chloroform-methanol (CM, 2:1, v/v) extracts from onion (Allium cepa L.) peels were studied. The $IC_{50}$ values of DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity in 70% ethanol extract were remained to be lowest followed by 70% methanol extract and CM extract. And the total phenol content ($113.56{\pm}0.86mg\;CAE/g$), total flavonoid content (49.63 mg QE/g) and ferric reducing antioxidant power value were also found to be the highest. In contrast, 70% methanol extract possessed the strongest antioxidant activity by ${\beta}$-carotene bleaching assay. CM extract displayed the lowest antioxidant activity compared with other extracts. Onion peels exhibited strong antioxidant activity and abundant phytochemicals, which could be used in a various food products to add phytochemicals and promote good health.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.860-866
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• 2010

This study was conducted to investigate the effects of dietary supplementation of garlic by-products on TBARS, WHC (water holding capacity), shear force, pH, total phenol content, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, meat color, sensory evaluation, and fatty acid composition of chicken meat. Broiler chicks were fed for 5 wk with experimental diets of 0% garlic by-product (Control), 1% garlic by-product (T1), 2% garlic by-product (T2), and 5% garlic by-product (T3). TBARS and pH were significantly decreased by the supplementation of garlic by-products compared to the control (p<0.05). Compared to the control diet, the total phenol content and DPPH radical scavenging activity were significantly increased by the supplementation of garlic by-products (p<0.05). The total phenol content and DPPH radical scavenging activity of treatment groups were higher than the control; in particular, T3 was significantly (p<0.05) more effective in improving freshness compared to other treatment groups. CIE $a^*$ value of treatment groups (especially T3) showed significantly higher values compared to the control; however, no difference in the CIE $L^*$ and $b^*$ values were observed among treatments. In its fatty acid composition, amounts of linoleic acid and linolenic acid in chicken meat was increased by the supplementation of garlic by-products, but amounts palmitic acid were decreased. In conclusion, supplementation with garlic by-products was effective in decreasing TBARS, pH, and saturated fatty acids, and in increasing total phenol content, DPPH radical scavenging activity, and unsaturated fatty acids.

• Journal of Life Science
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• v.33 no.7
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• pp.549-554
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• 2023

Korean ginseng has been used for centuries in traditional Chinese medicine as an overall wellness supplement. Red ginseng (Ginseng Radix Rubra) is produced by steaming the roots, followed by drying. Soft red ginseng is produced using a new processing technology. This study investigated whether soft red ginseng differs from raw and hard red ginseng in its physicochemical composition. Results showed that the total phenol content of raw ginseng was 2.96 mg/g at 80℃ and 3.47 mg/g at 160 ℃. Meanwhile, the total phenols of hard and soft red ginseng were 4.12 mg/g and 4.18 mg/g at 160℃, respectively. The total phenol contents of raw, hard red, and soft red ginseng revealed a statistically significant difference (p>0.05). The total flavonoid contents of raw, hard red, and soft red ginseng were 2.62 mg/g, 3.97 mg/g, and 3.83 mg/g at 160℃, respectively. Among the three samples, soft red ginseng had the highest total sugar content at 160℃. The acidic polysaccharide contents of both soft and hard red ginseng were much higher than that of raw ginseng (49%-58%). Significant differences were observed among raw, hard red, and soft red ginseng (p<0.001). Soft red ginseng exhibited higher phenol content (25%), total flavonoid content (49%), and total sugar content (45%) than raw ginseng.

• Korean journal of food and cookery science
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• v.30 no.1
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• pp.33-40
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• 2014

The purpose of this study was to examine the antioxidative activity of feral haw (Crataegus pinnatifida BUNGE) seed extracts using 70% methanol, 70% ethanol, chloroform:methanol (CM, 2:1, v/v), n-butanol and ethyl acetate (EA). The total phenol content of the five extracts ranged from 37.29 mg/g to 55.53 mg/g. Moreover, the content was high in the 70% methanol and, 70% ethanol extracts, but low in the n-butanol extract. On the contrary, the total flavonoid content decreased in the order of n-butanol (2.93 mg/g), EA (2.67 mg/g), 70% methanol (1.00 mg/g), 70% ethanol (0.88 mg/g) and CM (0.67 mg/g) extracts. The $NO_2$ radical scavenging activity, antioxidant activity by ${\beta}$-carotene bleaching assay and, superoxide dismutase (SOD) like ability decreased in the order of 70% methanol, 70% ethanol, CM, EA and, n-butanol extracts; further, a similar tendency was also observed in the total phenol contents. Overall, these results indicated that the antioxidative activity of feral haw seeds was closely related to the total phenol and flavonoid contents. Therefore, haw seeds might be usefully applied to natural antioxidants as well as functional foods.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.787-793
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• 1988

Juices of Golden Queen, Neo-Muscat and Seibell-9110 were prepared with the addition of $SO_2(100ppm)$ in must and juice, of $SO_2(100ppm)$ and pectinase (40mg/l) in must, respectively and then 300mg/1 of Polyclar AT were added on different white wines from grape juices. Phenolics content in grape juices and white wines were determined. and also changes of browning capacity of white wines during the storage periods at $45^{\circ}C$ were investigated by accelerated method. Extraction of total phenol into grape juices was increased significantly in $SO_2-pectinase$ addition lot and content of total phenol of Seibell-9110 juice was two or three times higher than the others. Yield of grape juices was highest in $SO_2-pectinase$ addition lot. Ethanol content of white wines were 11.4-12.0 v/v% , and total acid, fusel oil and methanol content of Neo-Muscat white wine was lower than that of the other white wines. Total phenol content of white wines was 25-50% lower than that of grape juices and 50-80% lower in colour. Browning capacity of white wines was decreased by 25-40% for 18 days at $45^{\circ}C$ with addition of Polyclar AT, but Seibell-9110 white wine prepared from $SO_2-pectinase$ addition lot was not available commercially because of severe browning.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.695-703
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• 2016

The purpose of this study was to measure the bioactivity and antioxidant activity of Orostachys japonicus A. Berger. Orostachys japonicus A. Berger have been known to contain functional materials such as kaempferol, hydroquinone, methyl gallate, quercetin, gallic acid etc. To identify the main functional materials of Orostachys japonicus A. Berger, the contents of flavonoid and phenol were measured. We extracted Orostachys japonicus A. Berger powder from four solvents such as chloroform:methanol (CM, 2:1, v/v), distilled water (DW), 70% methanol, 70% ethanol. After that, this study determined tannin, total phenol, flavonoid content, DPPH radical scavenging activity, ABTS radical scavenging activity, ferric reducing antioxidant power and reducing power of Orostachys japonicus A. Berger extracts and as results of comparing each extract. respectively. From the above results shows that antioxidant activity and bioactivity of Orostachys japonicus A. Berger extracts was higher in the order of 70% ethanol, 70% methanol, DW and CM (p<0.05). The results showed that antioxidant activity of Orostachys japonicus A. Berger extracts supposed to affect by the total phenol and flavonoid contents.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.445-449
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• 2006

Phenolic compounds are manufacturing by-products commonly found in industrial wastewater. The toxicity of high level phenolic compounds in wastewater threatens not only the aquatic organisms, but also many components of the adjacent ecosystem. One of the major light harvesting pigments in cyanobacteria is phycocyanin which can be rapidly and specifically degraded by external stimuli such as nutritional depletion or environmental stress. We employed the cyanobacterium Anabaena sp. PCC 7120 as an indicator organism in estimating the pollution level by phenolic compounds. The phycocyanin content of the cyanobacterium decreased without significantly altering the total chlorophyll as the phenol concentration in a medium increased. We examined the phenol contamination level using the correlation of the phycocyanin content and the phenol concentration. Our results indicated that no significant pollution by phenolic compounds was found in several waterbodies in the vicinity of Daegu, South Korea.