• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1307-1313
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• 2007

In order to evaluate the utilization of immature green wheat kernels as food processing material, these experiments were carried out to analyze general composition, free sugars, free amino acids, mineral content and color of 3 wheat varieties according to their heading dates. Contents such as moisture, crude protein, crude lipid and ash were gradually decreased according to the days after heading of 3 wheat varieties, while crude fiber and starch were gradually increased. Maltose and maltotriose contents in immature green wheat kernels were high but its rapidity decreased by closing to ripeness. Contents of free amino acids showed a tendency to decrease, among which alanine content was the highest around 25 days after heading, and then glutamic acid, GABA, glycine in order. Contents of total free amino acid were decreased by closing to ripeness. Among 3 wheat varieties, its contents of Guru wheat was the highest. As wheat matured, ${\beta}-glucan$ contents were decreased from 1.5% to 0.28% on 43 days after heading. Mineral contents of 3 wheat varieties were generally increased by closing to ripeness after coming into ears, and K, Mg were especially prominent. As wheat matured, lightness was decreased, while redness and yellowness were increased. Considering chemical composition and color, the immature green wheat were produced through blanching the spikes harvested before the yellow ripe stage. The harvested green wheat cereals is able to eat raw wheat or cook it as food processing material.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.170-172
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• 1989

It is preyed that marine algae, Chlorella pyrenoidosa can synthesize about 3.52% of eicosapentaenoic (EPA) of dry cell weight at the light intensity of 10 W/$\m^2$ which is optimal light intensity of producing EPA at $25^{\circ}C$. An equation to predict the amounts of EPA in the culture broth is derived as an exponential form with 0.91 of the correlation factor. The behavior of cell growth follows a photo-inhibition model by showing 12 W/$\m^2$ of saturation light intensity.

• Carbon letters
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• v.13 no.2
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• pp.61-72
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• 2012

Dye removal from waste water via adsorption by activated carbons (ACs) developed from agricultural wastes represents an ideal alternative to other expensive treatment options. Physical and chemical ACs were prepared from rice husks. The textural properties of the ACs were characterized by Brunauer-Emmett-Teller-$N_2$ adsorption and scanning electron microscopy. The chemistry of the carbon surface was investigated by Fourier transform infrared spectroscopy, base and acid neutralization capacities, pH of the active carbon slurry, and $pH_{pzc}$. The adsorption capacities of the ACs for the basic dye (methylene blue) and acid dye (acid green 25) were determined using parameters such as contact time, pH, and temperature. NaOH-ACs showed the highest surface area and total pore volume, whereas steam-ACs showed the lowest ones.

• Korean Journal of Metals and Materials
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• v.47 no.9
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• pp.558-566
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• 2009

The alloying effect of a small amount of nickel on low alloy steel for application to flue gas desulfurization(FGD) systems was studied. The structural characteristics of the rust layer were investigated by scanning electron microscopy(SEM). The electrochemical properties were examined by means of potentiostatic polarization test, potentiodynamic polarization test, and electrochemical impedance spectroscopy(EIS) in a modified green death solution of 16.9 vol.% $H_2SO_4$+0.35 vol.% HCl at $60^{\circ}C$ and an acid rain solution of $6.25{\times}10^{-5}M\;H_2SO_4+5.5{\times}10^{-3}M\;NaCl$ at room temperature. It was found that as the amount of nickel increased, the corrosion rate increased in the modified green death solution, which seemed to result from micro-galvanic corrosion between NiS and alloy matrix. In acid rain solution, the corrosion rate decreased as the amount of nickel increased due to the repulsive force of $NiFe_2O_4$ rust against $Cl^-$ ions by electronegativity.

• Corrosion Science and Technology
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• v.21 no.6
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• pp.423-433
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• 2022

The objective of this study was to determine whether Cymbopogon citratus extract as a corrosion inhibitor from natural tropical resources could prevent corrosion of carbon steel in sulfuric acid solution. Inhibitory action of this extract was investigated using electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Those methods revealed corrosion rate, efficiency of inhibition, and adsorptions isotherm values when the extract was added to the sulfuric acid solution at concentration up to 500 ppm with various immersion time at ambient temperature. Results revealed that higher concentration of the extract and longer immersion time decreased the corrosion rate of carbon steel whereas the inhibition efficiency of the extract was increased up to 97.25%. The value of charge transfer resistance was increased significantly by adding the extract at concentration up to 500 ppm with an immersion time of 60 minutes. The type of the extract was a mixed inhibitor. It could inhibit the corrosion process in both anodic and cathodic sides electrochemically. Results of this study suggest that the mechanism of adsorption on the surface of carbon steel is related to Langmuir adsorption isotherm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1025-1029
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• 2008

Fresh green tea leaf extracts were prepared by different enzyme treatment conditions, such as concentration, treating time and treating temperature using complex enzyme, Rapidase TF, and then extracted for 30 min at $80^{\circ}C$ to investigate their physicochemical properties. The results showed that free sugar content in every sample tended to increase, especially glucose content was increased up to 7.25 times compared to the control. Total amino acid was barely affected by the enzyme treatment and caffeine content was increased with reaction temperature. Total polyphenol and total catechin content was increased according to the amount of enzyme added and reaction temperature. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin gallate by descending order of the content. Gallic acid content increased up to 0.04% and $45^{\circ}C$ with no further significant changes thereafter. From the results above, we could conclude that a simple and new method to extract green tea materials directly from fresh green tea leaves with improved extract ratio may be introduced by adding $0.08{\sim}0.1%$ of Rapidase TF to heat treated fresh green tea leaves and keeping temperature at $37{\sim}45^{\circ}C$ for $180{\sim}240\;min$ in order to skip existing complicated procedures.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.67-74
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• 2015

Three strains of the green microalga Botryococcus braunii (JJS, KCM, and KJD) were isolated from different water bodies in Korea and grown as batch cultures in the laboratory. The effects of different growth media and temperatures on the growth rate were investigated, as well as the effect of temperature on the total lipid content and lipid profile. All three strains had the highest growth rates in BG-11 medium and at $25^{\circ}C$. Maximal lipid production ($gL^{-1}$) was at $30^{\circ}C$ in the JJS strain and at $25^{\circ}C$ in the KCM and KJD strains. However, all the three strains produced the greatest percent dry weight of total lipids at $15^{\circ}C$ and had the lowest percent dry weight of total lipids at $25^{\circ}C$. In general, oleic acid, linolenic acid, and behenic acid were the most common fatty acids in all three strains. However, the three strains varied considerably in their fatty acid profiles at different culture temperatures.

• ALGAE
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• v.31 no.1
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• pp.61-72
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• 2016

Arctic microalgae thrive and support primary production in extremely cold environment. Three Arctic green microalgal strains collected from freshwater near Dasan Station in Ny-Alesund, Svalbard, Arctic, were analyzed to evaluate the optimal growth conditions and contents of fatty acids. The optimal growth temperature for KNF0022, KNF0024, and KNF0032 was between 4 and 8℃. Among the three microalgal strains, KNF0032 showed the maximal cell number of 1.6 × 107 cells mL^-1 at 4℃. The contents of fatty acids in microalgae biomass of KNF0022, KNF0024, and KNF0032 cultured for 75 days were 37.34, 73.25, and 144.35 mg g^-1 dry cell weight, respectively. The common fatty acid methyl esters (FAMEs) analyzed from Arctic green microalgae consisted of palmitic acid methyl ester (C16:0), 5,8,11-heptadecatrienoic acid methyl ester (C17:3), oleic acid methyl ester (C18:1), linoleic acid methyl ester (C18:2), and α-linolenic acid methyl ester (C18:3). KNF0022 had high levels of heptadecanoic acid methyl ester (26.58%) and heptadecatrienoic acid methyl ester (22.17% of the total FAMEs). In KNF0024 and KNF0032, more than 72.09% of the total FAMEs consisted of mono- and polyunsaturated fatty acids. Oleic acid methyl ester from KNF0032 was detected at a high level of 20.13% of the FAMEs. Arctic freshwater microalgae are able to increase the levels of polyunsaturated fatty acids under a wide range of growth temperatures and can also be used to produce valuable industrial materials.

• Analytical Science and Technology
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• v.25 no.6
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• pp.460-466
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• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.734-740
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• 2001

The purpose of this study was to investigate the effect of green tea catechins on the antioxidative defense enzyme activity of kidney in diabetic rats. Sprague-Dawley male rats weighting 100$\pm$10g were randomly assigned to one normal and three STZ-induced diabetic groups; catechin free diet(DM-0C group), 0.25% catechin diet(DM-0.25C group) and 0.5% catechin diet(DM-0.5C group). Diabetes was induced by intravenous of 55mg/Kg body weight of STZ in sodium citrate buffer(pH 4.3) after 4 weeks feeding of experimental diets. Rats were sacrified at the 6th day of diabetic states. Superoxide dismutase(SOD) activity in kidney was decreased by 25% and 20% in DM-0C and DM-0.25C groups compared with normal group, DM-0.5C group was not significantly different when compared with normal group. Glutathione peroxidase(GSHpx) activity in kidney was were no significant differences the diabetic groups compared to normal group. Xanthin oxidase(XOD) activity was increased by 110% and 63% in DM-0C and DM-0.25C groups compared with normal group, DM-0.5C group was not significantly different when compared with normal group. The contents of superoxide radical(O$_2$)in kindney were 116% and 33%, respectively, higher in DM-0C and DM-0.25C groups than normal group. DM-0.5C group and normal groups were similar levels in their superoxide radical contents of kidneys. Levels of TBARS(thiobarbituric acid reactive substance) in kidney were increased by 62% in DM-0C group, when compared with normal group, but those of DM-0.5C group were similar to that of normal groups. These results indicate that free radical generation system was weakened and free radical scavenger system was enhance in kidney of STZ-induced diabetics rats by dietary catechin. Thereby it may reduce renal disorders such as oxidative damage and aging of tissue.