• Journal of Forest and Environmental Science
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• v.21 no.1
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• pp.16-23
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• 2005

The leaves of Paulownia Coreana Uyeki were collected, extracted with acetone-$H_2O$(7:3, v/v), fractionated with n-hexane, methylene chloride and ethylacetate, and freeze dried to give some dark brown powder. The ethylacetate soluble mixture was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. Spectrometric analysis such as NMR and MS including TLC were performed to characterize the structures of the isolated compounds. From the ethylacetate fraction, five flavonoides and three phenolic acids were isolated and determined.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.521-528
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• 2017

In this paper, the numerical analysis for heat conduction of silica/phenolic composite material, which is used for solid rocket nozzle liner or insulator, was conducted. 1-D Finite Difference Method for the analysis of silica/phenolic during the firing of solid rocket motor was used to calculate the heat conduction considering the surface ablation and the thermal decomposition. The boundary condition at the nozzle wall took into account the convective heat transfer, which was obtained by integration equation. The numerical results of the surface ablation and char depth were compared with the results of test motor that is TPEM-10. It was found that the result of calculation is favorably agreed with the thermal response of test motor.

• Journal of the Korean Society of Food Culture
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• v.30 no.6
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• pp.790-796
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• 2015

The objective of this study was to investigate the physicochemical properties and antioxidant activities of seven (A, B, C, D, E, F, G) commercial ketchups marketed in Korea. The 70% ethanol extracts were prepared and evaluated for total phenolic content, DPPH and ABTS radical scavenging activities, and metal chelating effect. pH ranged from 3.64 to 3.94, and soluble solid and reducing sugar contents of samples were 2.21~3.51oBrix and 4.78~13.45%, respectively. Salinity of samples was in the range of 1.79 to 3.21%, and sample G showed the lowest salinity. The lightness, redness, and yellowness of the Hunter color system of samples were 15.42~19.94, 18.55~23.98, and 20.87~24.34, respectively. The phenolic contents ranged from 1.37 to 2.60 mg GAE (gallic acid equivalents)/g, with samples F and G exhibiting the highest contents. Antioxidant activity determined based on DPPH and ABTS radical scavenging activities, and metal chelating effects were 45.10~90.87, 55.35~92.53, and 71.10~92.20%, respectively, at a concentration of 200 mg/mL. Samples A and G showed higher antioxidant activity than other samples. There were positive correlations between phenolic contents and antioxidant activity, suggesting that phenolic compounds are the major contributors to antioxidant activity.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.5 s.113
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• pp.50-55
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• 2005

In previous report, we investigated the impact of hexeneuronic acid and some residual extractiveson lignin determination. These non-lignin components severely interfered lignin content determination which also affect on the oxygen delignification comparison between aspen and pine unbleached kraft pulps. Very different pattern was observed whether based on uncorrected conventional kappa number or based on corrected kappa number in oxygen delignification comparison. Lower kappa number aspen pulps showed poor response to oxygen delignification when kappa number was used as lignin determination method but better response with using the acid lignin method. Phenolic hydroxyl group in kraft pulps were also compared based on uncorrected or corrected kappa numberfor lignin content. Based on uncorrected kappa number, lower kappa number oxygen-delignified pulps had lower phenolic hydroxyl group. However, lower kappa number oxygen-delignified pulps showed much higher phenolic hydroxyl group based on the corrected lignin content. For accurate comparison for residual lignin properties from different pulps, lignin determination should be corrected from non-lignin components contribution to lignin.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.76-84
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• 2018

In this paper, the numerical analysis for heat conduction of silica/phenolic composite material, used for solid rocket nozzle liners or insulators, is conducted. A 1-dimensional finite difference method for the analysis of silica/phenolic during the firing of a solid rocket motor is used to calculate heat conduction, considering surface ablation and thermal decomposition. The boundary condition at the nozzle wall, considering the convective heat transfer, is obtained via integration equations. The numerical results of the surface ablation and char depth are compared with the results of a TPEM-10 test motor, finding that the result of calculation agrees with the thermal response of the test motor.

• International Journal of Advanced Culture Technology
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• v.7 no.3
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• pp.120-125
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• 2019

In this paper, we have isolated six phenolic compounds, such as (+)-catechin (1), taxifolin (2), taxifolin-3-O-${\beta}$-D-(+)-xylose (3), quercetin (4), quercetin-3-O-${\alpha}$-L(+)-rhamnose (quercitrin) (5), apigenin-8-C-rhamnosyl-(1'''${\rightarrow}$2'')-glucoside (2''-O-rhamnosylvitexin) (6) from the EtOAc(Ethyl Acetate) and $H_2O$ soluble fractions of Japanese anise(Illicium anisatum L) leaves and twigs. Also, we have evaluated antioxidative and antiviral activity for each isolated compound. The antioxidative test was DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. According to the experimental results, all of the isolated compounds indicated the increased radical scavenging activities as the concentration increases and most of the isolated compounds indicated generally good antioxidative values compare to the controls, ascorbic acid and ${\alpha}$-tocopherol. In the antiviral activities, all of the isolated compounds had no potentials in rhinovirus 1B (HRV 1B). But in enterovirus 71 (EV 71) and Influenza virus A/PR/8 (Influenza PR8), only quercetin (4) indicated the good antiviral activity compare to the control. Based on the above results, we found that the phenolic compounds of Japanese anise may be applied for one of the natural biomass sources that can be used as an antioxidant and an antiviral substance.

• Natural Product Sciences
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• v.25 no.1
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• pp.44-48
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• 2019

Nelumbo nucifera Gaertn. (Nymphaeaceae) is commonly called lotus and its leaves are widely been used as functional ingredients due to its antioxidant activity. For maximum efficacy, optimized extraction condition was established using response surface methodology. The high F-values, low p-values and insignificant p-value for lack-of-fit supported the fitness of the model and yielded the second-order polynomial regression for the antioxidant activity. The optimized extract was obtained by the extraction of 1 g of lotus leaves with 40 mL of 50% MeOH at $10.0^{\circ}C$, which exerted 70.1% antioxidant activity. Close correlation between phenolic content and antioxidant activity suggested phenolic compounds as active constituents of lotus leaves. In addition, comparison of different parts of lotus demonstrated the most potent antioxidant activity of flowers, followed by leaves and roots. Taken together, these results provide useful information about lotus leaves for the development as antioxidant ingredients. In addition, flowers and roots as well as leaves are suggested as good sources for antioxidant activity.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.297-303
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• 2020

Berries are rich sources of phenolic compounds, which are known to have health-promoting effects. In this study, phenolic compounds of seven popularly consumed berries were analyzed by HPLC-ESI-MS/MS. In addition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and nitrite scavenging activities were investigated for comparison of the biological activity of the berry extracts. Chlorogenic acid was the major phenolic acid, which had the highest content in aronia, followed by blueberry. The rutin and isoquercetin contents were the highest in mulberry, followed by aronia, black raspberry, and blueberry. The anthocyanin content was the highest in black raspberry. Aronia showed the highest DPPH free radical and nitrite scavenging activities with the highest contents of total phenolics and proanthocyanidins.

• Journal of the Korean Society of Food Culture
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• v.38 no.6
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• pp.456-464
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• 2023

The purpose of this study was to investigate nutritional and functional ingredients and antioxidant activity after fermenting rice bran using Lactobacillus brevis for 24, 36, and 48 hours. The results of the analysis of the nutritional ingredients revealed that there was no significant difference in the carbohydrate, crude protein, crude fat and ash content regardless of the fermentation process and fermentation time. The amount of dietary fiber was significantly different between the unfermented and fermented rice bran and was observed to be the highest after a 48-hour fermentation. The γ-oryzanol, gamma-aminobutyric acid (GABA) and total phenolic contents were significantly higher in the fermented rice bran compared to the unfermented rice bran (p<0.05) and the GABA and total phenolic contents increased significantly as the fermentation time increased (p<0.05). The 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), superoxide and hydroxyl radical scavenging activities used to measure antioxidant effects significantly increased as the fermentation time increased (p<0.05). From these results, it was confirmed that the antioxidant effect and functional components, namely γ-oryzanol, GABA, and the total phenolic content of rice bran improved with fermentation. Based on these results, fermented rice bran could be presented as a functional material for use in high value-added industries.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.566-570
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• 2013

Vaccinium oldhamii Miq. is a Korean native tree, which is deciduous and shrub tree with broad leaf. To develop superior cultivars for edible or medicinal purposes, we evaluated total phenolic content and antioxidant activity. Total phenolic content was measured by folin-denis method and antioxidant activity was measured by DPPH free radical scavenging activity (DPPH method) and reducing power (potassium ferricyanide method). Total phenolic content, DPPH free radical scavenging activity (at 400 ppm) and reducing power (at 700 ppm) were 15.8~19.9 mg/g, 69.1~91.4% and 0.56~0.96, respectively. A linear correlation was shown between DPPH-radical scavenging activity and reducing power (r=0969).