• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.200-208
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• 2004

This study was performed to investigate the change of biologically functional compounds and antioxidant activities in Hizikia fusiformis with drying methods. As biologically functional compounds, the contents of minerals(K, Ca, Ma, Mg, Fe, Cu, Mn and Zn), vitamins(vitamin C, ${\beta}-carotene\;and\;{\alpha}-tocopherol$) and total polyphenol were analyzed. And antioxidant activity was determined through free radicals(DPPH radical, superoxide anion radical, hydroxyl radical and hydrogen peroxide) scavenging activity and linoleic acid peroxidation inhibitory activity. The contents of minerals were not affected by drying methods however vitamins and total polyphenol were lost more by sun-drying than other drying methods studies. Total polyphenol was preserved by freezing-drying than other drying methods studies, resulting in high antioxidant activities.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.527-538
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• 2023

The aim of this study was to investigate the antioxidant effects of O. robusta stem extract (ORE) and to determine the total polyphenol and flavonoid contents. Free radical scavenging properties were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)), and ·OH (hydroxyl radical) scavenging assays. Total polyphenol and flavonoid contents were measured using Folin-Ciocalteu reagent and aluminum chloride colorimetric methods, respectively. Active compounds of ORE were determined using high-performance liquid chromatography (HPLC). The results of the study showed that ORE exhibited DPPH, ABTS, and ·OH radical scavenging activities in a dose-dependent manner. Especially, 1,000 ㎍/mL of ORE showed the strongest radical scavenging properties against DPPH, ABTS, and ·OH. ORE contained total polyphenol content of 57.4 mg GAE/g and total flavonoid content of 5.4 mg QE/g, which may contribute to their antioxidant effects. As a result of HPLC, the contents of active compounds in ORE, dihydrokaempferol (0.65 ㎍/mL), and 3-O-methylquercetin (1.10 ㎍/mL) were confirmed. In conclusion, ORE may be useful as a functional material with antioxidant properties.

• Analytical Science and Technology
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• v.11 no.6
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• pp.478-484
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• 1998

Distribution of polyphenolic compounds in oak tree (Quercus acutissima, three years old) collected from Forest Research Institute located in Kwang Leung, Kyeonggi-do, Korea, was investigated using chromatographic studies. Total 25 polyphenolic fractions were separated from an oak tree, of which 15, 11, 7, 7, and 4 were in leaf, stem, root, bark, and seed, respectively. Catechins are predominant compounds in the polyphenols and some flavonoids were also identified. Distribution of polyphenols was relatively different in each part. Polyphenols in all of the part studied, except leaf where polymer was not detected, were existed as polymeric, oligomeric, and monomeric forms. Relative contents of total polyphenols in Quercus acutissima were the highest in bark, followed by root, leaf, acorn, and stem. Monomeric polyphenols were the predominant compounds present in all of the part of the oak tree.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.397-401
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• 2008

Changes in the contents of total phenolic compounds in as Agrimonia pilosa well as their antioxidant capacity according to the havest time and positions were examined. The contents of the total phenolic compounds were determined by extraction with MeOH. Among havest times harvestry in July showed highest contents of the total phenolic compounds and harvestry in May showed lowest contents of the phenolic compounds. Among the 4 positions (root, branch, leaf, flower) of Agrimonia pilosa the root contained highest contents of the phenolic compounds. The antioxidant capacities of Agrimonia pilosa were increased roughly with increasing level of contents of phenolic compounds according to positions.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.268-273
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• 2005

Changes in contents of phytochemical compounds (${\beta}$-carotene, ascorbic acid, chlorophylls, total flavonoid, total polyphenol) and hazardous factors (microbial counts, nitrate) of spinach (Spinacia oleracia L.) were investigated by conventional and microwave blanching methods. ${\beta}$-Carotene and chlorophylls contents of spinach were significantly increased by blanching, with conventional blanching resulting in higher contents than microwave blanching. In contrast, contents of ascorbic acid, total flavonoid, and total polyphenol of blanched spinach decreased, with microwave blanching resulting in higher ascorbic acid, total flavonoid, and total polyphenol contents than conventional blanching. Total plate count and total coliforms of blanched spinach significantly decreased, with conventional blanching showing less than 20-25% of microwave blanching. Nitrate content of blanched spinach also showed decreasing pattern, with decrease due to microwave blanching being lower, although not significantly, than that of conventional blanching.

• Korean Journal of Pharmacognosy
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• v.48 no.3
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• pp.208-212
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• 2017

In this study, analysis of active compounds that are believed to be highly relevant to antioxidant activity was carried out on the methanol extract and its solvent fractions of Corni fructus. The DPPH radical scavenging activity for the comparison of antioxidant activity was higher in order of aqueous fraction > methanol extract > ethyl acetate fraction > n-hexane fraction. It is similar to the order of total polyphenol contents in the samples. As a result of LC-MS analysis, phenolic acid compounds such as caffeic acid, gallic acid and chlorogenic acid and lognin, which is known as a representative active ingredient of Corni fructus, were identified as active compounds. And the antioxidative activity and the total polyphenol content of the extracts and solvent fractions were found to be related to the contents of the compounds. Particularly, it was confirmed that phenolic acid such as caffeic acid contributes to the antioxidative activity of the aqueous fraction of Corni fructus methanol extract.

• Journal of the Korean Society of Food Culture
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• v.19 no.4
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• pp.369-377
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• 2004

This study was performed to investigate the change of biologically functional compounds and antioxidant activities in Ecklonia cava with blanching times. As biologically functional compounds, the contents of minerals(K, Ca, Na, Mg, Fe, Cu, Mn and Zn), vitamins($vitamin\;C,\;{\beta}-carotene\;and\;{\alpha}-tocopherol$) and total polyphenol were analyzed. And antioxidant activity was determined through free radicals(DPPH radical, superoxide anion radical, hydroxyl radical and hydrogen peroxide) scavenging activity and linoleic acid peroxidation inhibitory activity. As the blanching time increased, the contents of minerals, vitamin C, ${\beta}-carotene$ and total polyphenol were decreased however ${\alpha}-tocopherol$ was not affected by blanching time, and antioxidant activities were decreased with blanching time.

• Korean Journal of Medicinal Crop Science
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• v.24 no.4
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• pp.263-270
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• 2016

Background: In this study, microwave extraction was used, which is an effective method to extract useful bioactive substances as it requires low quantities of solvent and short time periods. The aim of this study was to determine the optimal extraction conditions for Agrimonia pilosa Ledeb. Methods and Results: The independent variables were ethanol concentration, microwave power, and extraction time, each of which had five levels. The dependent variables were total polyphenol and total flavonoid content, and DPPH radical scavenging activity. To determine the optimal extraction conditions for bioactive compounds, a response surface methodology was employed. Contour maps were generated from polynomial equations. The optimal conditions were then assumed by superimposing these contour maps. Based on the resulting graph, the optimal microwave extraction conditions for Agrimonia pilosa Ledeb were determined as 42 - 48% ethanol concentration, 240 - 280W microwave power, and 13 - 20 min of extraction time. Conclusions: Ethanol concentration had a significant effect on microwave extraction, in terms of total polyphenol and total flavonoid content, as well as DPPH radical scavenging activity. Microwave power and extraction time influenced the total polyphenol content, but not the total flavonoid content or the DPPH radical scavenging activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.6-13
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• 2001

The study was conducted to investigate the effect of the browning inhibitors such as PVPP(polyvinylpoly-pyrrolidone), A.A.(ascorbic acid) on nonezymatic browning factors [free sugar, total amino acid, organic acid, A.A., HMF (hydroxymethylfurfural)] and enzymatic browning factors [PRO (polyphenoloxidase) activity, polyphenol compounds] in concentrated apple juice during 90 days storage. Considering color value (L value, $\Delta$E), absorbance at 420 nm, concentrated apple juice during 90 days storage. Considering color the effect of browning inhibition. According to the storage period, the changes of nonenzymatic factors in concentrated apple juice added with browning inhibitors were similar to those in control (concentrated apple juice without browning inhibitors), which were the decreased of sucrose(0.24~0.35% at 90 days), the slight increase of glucose and fructose, the decrease of total amino acid (530.4~573.1 mg/10g at 90 days), same value of A.A. at 90 days (38.5~78.6 mg/100g), and the increase of HMF (27.8~30.6 mg/100g at 90 days). On the contrary, enzymatic browning factors were significantly inhibited in concentrated apple juice added with PVPP, judging from the slow increase of PRO activity and the significant decrease of initial value in polyphenol compounds (especially chlorogenic acid). These results suggest that PVPP plays an important role as enzymatic browning inhibitor, that is, a scavenger of polyphenol compounds by adsorption in concentrated apple juice.

• Korean Journal of Medicinal Crop Science
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• v.17 no.1
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• pp.21-25
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• 2009

The results on the useful functional compounds of kenaf (Hibiscus cannabinus L.) leaves cultivated in reclaimed lands and the biological activity effects of extracts were as follows. On 98 days after sowing (DAS) Tainung-2 showed the highest total chlorophyll content (1.68 mg/g), and on 141 DAS Dowling showed higher chlorophyll content (1.50 mg/g) than the other two did. In all cultivars the total chlorophyll content was higher on 141 DAS than on 98 DAS. Total polyphenol and total flavonoid contents were the highest in Tainung-2 (30.50 mg/g and 57.03 mg/g, respectively), and total polyphenol and total flavonoid contents (30.50 mg/g and 57.03 mg/g, respectively) were the highest in 30% ethanol extraction. Ascorbic acid contents were higher on 141 DAS than on 98 DAS in three cultivars. SOD activities of kenaf leaf extract were generally over 90%. DPPH radical scavenging activity of Tainung-2 was higher than others.