• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.79-86
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• 2010

Effects of operating parameters such as applied voltage, solution conductivity, ferrous ion concentration, electrode material on phenol degradation by pulsed corona discharges were investigated in laboratory scale experiments. The increase of applied voltage enhanced the phenol degradation by generating more energetic electrons. The solution conductivity inversely affected phenol removal rate in the tested ranges because the increase of conductivity decreased the electric field strength through the liquid phase. The addition of ferrous sulfate promoted the phenol degradation through the OH radical production by the Fentonlike reactions between ferrous ion and hydrogen peroxide generated by pulsed corona discharges. Catechol and hydroquinone were detected as primary intermediates of phenol degradation and the decrease of pH and the increase of conductivity were observed probably due to the generation of organic acids. Almost all of the initial phenol was disappeared and 29% of total organic corbon (TOC) was removed in the condition of 0.5 mM of ferrous sulfate after approximately 230 kJ of discharge energy transferred to the reactor.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.593-597
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• 2010

This study investigated the properties and antioxidative activities of phenolic acid concentrates of rice bran. Rice bran contains bioactive substances such as phenolic compounds, which can provide health benefits as natural antioxidants. This study examined how levels of phenolic acids can be obtained efficiently through various extraction methods. The extractions of defatted rice bran were followed by using ethylacetate (RBE-I), ethylacetate after alkaline hydrolysis (RBE-II), and 80% methanol (RBE-III). For all extracts, yields (%), total polyphenol contents (TPC), various phenolic acids and antioxidative activities were estimated. RBE-II had the highest total polyphenol contents (526.72 mg/100 g rice bran) and showed high antioxidative activity (74.7%). To concentrate the phenolic acids, RBE-II was passed through Sep-pak $C_{18}$ Vac cartridge and F1-RBE-II was collected by the elution of 50% methanol. The total phenolic content of F1-RBE-II (736.8 mg/100 g rice bran) was higher than that of RBE-II (367.1 mg/100 g rice bran), and the ratios of ferulic acid (73%) and sinapic acid (14%) increased. As RBE-II was analysed by HPLC, 6 different phenolic acids were found via chromatography, whereas F1-RBE-II showed 5 different peaks and the major phenolic acid was identified as ferulic acid. The ABTS radical scavenging activity of F1-RBE-II was the highest among the rice bran extracts. In a ${\beta}$-carotene-linoleic acid model system, linoleic acid oxidation was reduced by F1-RBE-II (73%) and RBE-II (35%).

• Food Science and Preservation
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• v.11 no.2
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• pp.207-213
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• 2004

Methanol extracts were prepared from 32 medicinal herbs of the extracts were tested their microbial inhibition activities against food borne pathogens and/or food poisoning microorganisms, food-related bacteria and yeast. Methanol extracts of Cinnamomum cassia, Paeonia suffruticosa, Alnus japonica, Eugenio caryophyllata and Illicium verum exhibited antimicrobial activity for the microorganisms tested, except lactic acid bacteria and yeast. Minimum inhibitory concentrations(MIC) were about 5 mg/mL for Bacillus subtilis, Staphylococcus epidermidis and Pseudomonas aeruginosa. Cell growth of lactic acid bacteria was inhibitied, but greatly on Leuconostoc mesenteroides. The phenolic compound contents were 10.98 mg/g, 10.31 mg/g, 8.55 mg/g and 6.69 mg/g in Thea sinensis, Eugenia caryophyllata, Alnus japonica and Artenisia capillaris, respectively. Antimicrobial activity appeared to be related to phenol compound content in medicinal herbs. The methanol extracts of medicinal herbs could be suitable for the development of a food preservative.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.581-585
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• 1999

The antioxidative activity measured by electron donating ability was investigated for the breeding of the highest antioxidative waxy corn (Zea mays L.) and the research for the most effective antioxidant in waxy corn. The electron donating ability was $15.5{\sim}65.0%$. The contents of phenolic compounds and tocopherols and the absorbance at 450 nm were $102.3{\sim}323.5\;{\mu}g/mL$, $15.6{\sim}144.2\;{\mu}g/mL$ and $0.047{\sim}0.206$, respectively. The mean values of electron donating ability and contents of phenolic compounds and tocopherols of four black waxy corn were comparatively high, that is, 48.7%, $267.0\;{\mu}g/mL$ and $87.0\;{\mu}g/mL$, respectively. The electron donating ability was significantly correlated with the level of phenolic compounds and tocopherols but not with the content of carotenoids.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.693-697
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• 2016

In this study, the electron donating ability(EDA) and total polyphenol content of herbal wine were examined. The herbal wine was obtained from extract concentration to evaluate its functional properties. The herbal wine were screened for their potential antioxidant activities using test such as electron donating ability(EDA) and total polyphenol content. The electron donating ability(EDA) were $21.81{\pm}0.56$ in herbal wine 15% and $40.45{\pm}1.60$ in herbal wine 35%. As the extract concentration was increased the electron donating ability(EDA) were significantly increased(p<0.05). The total polyphenol contents were measures $113.89{\pm}1.79{\mu}g\;GAE/m{\ell}$ in herbal wine 15%, $274.24{\pm}0.71{\mu}g\;GAE/m{\ell}$ in herbal wine 35%. As the extract concentration was increased the total polyphenol contents were significantly increased(p<0.05). Also, the total polyphenol contents were measures $61.75{\mu}g\;GAE/m{\ell}$ in herbal wine, the higher.

• Culinary science and hospitality research
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• v.21 no.5
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• pp.171-179
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• 2015

This study was conducted to investigate the antioxidant activity and the bioactive compounds found in 70% ethanol extracts taken from Sanguisorbae officinalis L. leaves(SO) cultivated in Korea. The extracts were tested for their total phenolic contents (TPC), total flavonoid contents (TFC), phenolic compounds, and antioxidative activities using various in vitro assay such as DPPH, ABTS radical scavenging activity, FRAP activity, and reducing power. The TPC and TFC were found to be $119.3{\pm}1.54mg$ gallic acid and $59.6{\pm}1.43mg$ rutin at mg of 70% ethanol extracts, respectively. Catechin was the major material among the phenolic compounds in SO extracts. The DPPH radical scavenging activity, ABTS radical scavenging activity, FRAP activity, and reducing power of SO extracts were increased in a dose-dependent manner. These results suggest that SO extracts could be considered as a good source of natural antioxidants and functional food ingredient.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.198-202
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• 2018

The present study aimed to investigate the effect of germination and temperature on the antioxidant activity of coffee. Green beans were germinated at 20 and $40^{\circ}C$. Germinated green beans were dried and roasted. Ground coffee was brewed at $90^{\circ}C$ for 5 min. Coffee samples were analyzed for antioxidant compounds and for its antioxidant activity. The total polyphenol content (TPC) and total flavonoid content (TFC) in coffee brewed with coffee beans germinated at $20^{\circ}C$ (CG20) were significantly higher than those in coffee brewed with non-germinated coffee beans (CNG). The same tendency was observed on 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging assays. TPC and TFC of coffee brewed with germinated coffee beans decreased with an increase in germination temperature from 20 to $40^{\circ}C$. In conclusion, germination of coffee beans contributes to an increase in its antioxidant activity. However, setting the appropriate temperature for germination is an important factor in determining the antioxidant activity of coffee.

• 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.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1321-1326
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• 2005

As a results of this research, the Nakdong River consisted of 43% of hydrophobic fraction, 39% of hydrophilic fraction, and 18% of transphilic fraction. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional roup(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores. The carboxylic acid functional group caused more fouling than the phenolic group.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1124-1129
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• 2008

Cokes wastewater is one of the most toxic industrial effluents since it contains high concentrations of pollutants, such as phenol, ammonia, thiocyanate and cyanides. Although biological pre-denitrification process has been used to treat this wastewater in Korea, unexpected failure in nitrogen removal occasionally occurs during summer season. In this study, therefore, we examined inhibitory effects of phenol, ammonia, thiocyanate, ferric cyanide and free cyanide on biological denitrification according to temperature variation ($20{\sim}38^{\circ}C$). Batch experiments showed that denitrification rate was faster in summer ($38^{\circ}C$) than other seasons, and removal rates of pollutants increased with increasing temperature. Phenol, ammonia, thiocyanate and ferric cyanide did not inhibit denitrification even at its high concentration (200 mg/L). However free cyanide above 0.5 mg/L seriously inhibited the bilolgical denitrification reaction. Inhibitory effect of these pollutants was reduced with increasing temperature.