• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.733-738
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• 2010

The leaves of Zizyphus jujuba have been used for various purposes including medicine and nutrition. In this study, the conditions for the ethanol extraction of antioxidant from Zizyphus jujuba were optimized using response surface methodology (RSM). A Box-Behnken design containing 15 experimental runs with three replicates was employed to study the effects of solvent extraction conditions such as extraction temperature ($^{\circ}C$, $X_1$), extraction time (min, $X_2$), and ethanol concentration (%, $X_3$) on the extraction yield of antioxidants from Zizyphus jujuba. The yields of total polyphenols and total flavonoid, and electron donating activity (EDA) were considered as response variables. The second-order polynomial model gave a satisfactory description of the experimental results showing different patterns of extraction conditions with variation in the linear, quadratic, and interaction effects of the independent variables. Based on four-dimensional RSM, one of the optimized sets of conditions was 45% ethanol, $45^{\circ}C$, and an extraction time of 15 min. Under the optimal conditions, the predicted values were 177.64 mg/g dry basis, 35.99 mg/g dry basis, and 86.14% Vit.C equivalents for total polyphenols, total flavonoids, and EDA, respectively. The experimental values showed good agreements with the predicted values.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1476-1483
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• 2015

This study was conducted in order to compare changes in the quality characteristics and antioxidant activity of mulberries depending on the degree of ripeness between greenhouse (GH) and open field (OF) cultivation. The mulberries were divided into five degrees of ripeness. Quality characteristics such as pH, acidity, antioxidant activity, and contents of free sugar, organic acid, polyphenols, flavonoids, and anthocyanins were investigated. pH level increased slightly while acidity decreased depending on the degree of ripeness. Fructose and glucose were detected in mulberries as the major free sugar. Fructose and glucose increased rapidly during ripening. Citric acid was major acid and decreased considerably during ripening. Contents of total polyphenols, flavonoids, and anthocyanins increased considerably in the last stage of ripening. Contents of polyphenols, and flavonoids in mulberry from OF were higher than from GH. DPPH and ABTS radical scavenging activities increased rapidly in mulberries of the last degree. Contents of functional components were not greatly different between GH and OF, whereas content of free sugar in GH was higher than that in OF.

• Journal of the Korean Applied Science and Technology
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• v.39 no.3
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• pp.417-422
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• 2022

We tried to check the antioxidant activity and toxicity of trichosanthis cucumeroidis radix extracts in skin cells, and check the possibility of their use as a functional material that can be effectively used on the skin. Total polyphenol and total flavonoid content, which are indicators of antioxidant activity of trichosanthis cucumeroidis radix extracts, were confirmed, and cytotoxicity was confirmed using Neutral red assay in the skin. As a result of the study, the content of total polyphenols and total flavonoids increased concentration-dependent. High survival rates in fibroblast HDF cells were identified, and cell survival rates were significantly lowered from 5 ㎍/mL in melanocytes B16F10 melanoma cells and inflammation-related macrophages RAW 264.7 cells. He results of this study are believed to be available as basic data for antioxidant activity of trichosanthis cucumeroidis radix extracts and skin cells.

• Food Science and Preservation
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• v.14 no.6
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• pp.709-715
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• 2007

Korean green tea has been claimed to have health-promoting effects, which may be related to the antioxidant activity in vitro. Korean green teas (Woojeon, WJ ; Sejak, SJ ; Jungjak, JJ ; Daejak, DJ) were subjected to different harvested times and yet little research has examined their bioactive compounds. To assess the effect of this different harvested times on nutritional and health-related properties such as Korean green tea polyphenols, flavonoids, theanine and free amino acids, antioxidant activities and radical scavenging activities were determined. Total polyphenols in JJ (37.16 mg/g) was higher than in other products (WJ, 19.55 ; SJ 24.65 ; DJ, 23.28 mg/g). Contents of flavonol and flavone glycosides were the highest at DJ (350.83 mg%) as compared to WJ (220.81), SJ (256.88) and JJ (270.36 mg%). Contents of theanine and total free amino acids were the highest at WJ (14.11, 23.62 mg/g, respectively), but decreased thereafter. Antioxidant activities were higher in JJ and DJ, using the linoleic acid peroxidation, DPPH and ABTS free radical-scavenging activities. However, WJ and SJ had less active antioxidant activity and free radical-scavenging activity. Reducing powers were increased depend on the concentration of extracts. Antioxidant activity and free radical-scavenging activity of JJ and DJ seemed to relate with total polyphenol and flavonoid contents.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.110-110
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• 2018

The purpose of this study was to evaluate the improved antioxidant activity of Aronia extract fermented by lactic acid bacteria isolated from fermented seafoods. Aronia fruits were collected from Sunchang, Chonbuk, South Korea. And these collected fruits were lyophilized for fermentation. For the selection of effective lactic acid bacteria useful for fermentation. Aronia fermented by lactic acid bacteria that isolated from fermented seafood was extracted with 60% ethanol. Antioxidant activity of Aronia extract was evaluated on the DPPH radical scavenging activity and total polyphenol contents were studied. To determine the optimal fermentation conditions, the changes of antioxidant efficacy was evaluated by controlling temperature (25, 30, 37, $40^{\circ}C$), Time (0~5 day) and inoculation dose of lactic acid bacteria (0.125~0.5ml). To confirm the antioxidative effect of Aronia fermented under optimal conditions, the DPPH & ABTS radical scavenging activity, total polyphenol & flavonoid contents were compared before and after fermentation were studied. 16 different kinds of lactic acid bacteria were isolated from fermented seafood, and of which antioxidant activity of Aronia fermented by Pediococcus pentosaceus B1 was maximum. Aronia fermentation at $37^{\circ}C$ was maximized when fermented for 3 days and fermentation time is decreased as the start inoculation amount of lactic acid bacteria increased. The degree of increase in antioxidant activity after Aronia fermentation is that DPPH & ABTS radical scavenging activity was increased about 27%, 20% and total polyphenols & flavonoids contents was increased about 12%, 15%. In the result of this experiment indicated that fermentation process enhances the antioxidant efficacy of Aronia.

• 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 Chemical Engineering Research
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• v.56 no.1
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• pp.66-72
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• 2018

Corn stover is known as a good candidate for a functional food ingredient when the main lignocellulosic material, lignin, is used as bioactive materials as form of polyphenolic compounds. The purpose of this study was to determine the microwave extraction conditions under which total phenolic compounds (TPC) and flavonoid contents of corn stover were maximized. Microwave-assisted extracts using sulfuric acid ranging from 0 to 1.0 mol with extraction time between 40 and 240 sec were conducted by using response surface methodology (RSM). Microwave power showed significant effects (p<0.05) and the concentrations of TPC and flavonoids increased with increased level of microwave power and extraction time. The optimum conditions for corn stover extraction were determined as 698.6 W, 240 sec, and 0 mol sulfuric acid, and the predicted value of TPC and flavonoid is 82.4 mg GAE/g DM and 18.1 mg/g DM, respectively. Microwave extraction was evaluated as an economic process with low energy consumption, short extraction and high extraction yield of bioactive including TPC and flavonoids compared to conventional extractions.

• Food Science and Preservation
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• v.14 no.2
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• pp.177-182
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• 2007

This study was performed to investigate the antioxidant effect of 80% (v/v) ethanol extract from Chaenomelis Fructus (CF). Total flavonoids and total polyphenols in the extract were also measured spectrophotometrically. The extraction yield was 9.23g/100g CF. The extract was further fractionated by partition with n-hexane, chloroform, ethylacetate, butanol, and water. The water fraction showed the highest extraction yield of all fractions. The n-hexane method and compared with the properties of the commerical antioxidant BHT. The activities of the n-hexane fraction were the highest of all fractions. In addition, there was strong positive correlation between antioxidant activities and levels of antioxidative compounds, such as flavonoid and polyphenols, in CF fractions, suggesting that these antioxidative compounds may contribute to the antioxidative effect of CF.

• Journal of the Korea Convergence Society
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• v.8 no.12
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• pp.109-117
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• 2017

The purpose of the study aimed to explore the possibility for natural preservative convergence materials by examining the antioxidant activity and antimicrobial effect of 19 wild plants in Jiri Mountain. Total polyphenols were higher in the order of CS(Camellia sinensis L., 87.9 mg GAE/ g), MP(Mentha piperascens Holmes., 85.1 mg), NN(Nelumbo nucifera Gaertn., 65.0 mg) and PD(Pinus densiflora Siebold & Zucc., 52.8 mg). Total flavonoids were high in NN(25.7 mg QUE / g) and MP (25.4 mg QUE / g). CS(58.1%), NN(47.9%), and MP(40.6%) showed high ABTS radical scavenging ability and the result was similar in DPPH radical scavenging ability. The extracts of HC(Hemerocallis coreana Nakai.), PD, and CO(Cornus officinalis Siebold et Zucc.) showed the highest inhibitory effect on the growth of E. coli. The extracts of PK(Pulsatilla koreana Nakai ex Nakai.), SC(Saururus chinensis Baill.), and MC(Smilax china L.) completely inhibited the proliferation of S. aureus, showing the possibility to be developed as natural preservatives and disinfectants.

• Korean Journal of Plant Resources
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• v.20 no.2
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• pp.185-192
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• 2007

The different parts of 8 edible and medicinal ferns were extracted with 80% ethanol and the bioactive substances and antioxidant activities were investigated. Total polyphenol content was highest in Cyrtomium fortunei rhizome ($57.32mg{\cdot}g^{-1}$) and followed by C. fortunei root, Pyrrosia lingua aerial part and Onoclea sensibilis var. interrupta aerial part. Total flavonoid contents ranged from 1.95 (Onoclea sensibilis var. interrupta rhizome) to $27.51mg{\cdot}g^{-1}$ (O. sensibilis var. interrupta aerial part). Among the samples tested, C. fortunei root and rhizome were found to be most effective in both DPPH and ABTS radical scavenging assay. Except in Selaginella tamariscina underground part and Osmunda japonica aerial part, most of the tested samples showed strong potential (above 87%) in inhibition rate on linoleic acid oxidation.