• Economic and Environmental Geology
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• v.35 no.4
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• pp.325-337
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• 2002

We examined the contamination of stream water and stream sediments by heavy metal elements with respect to distance from the abandoned Backun Au-Ag-Cu mine. High contents of heavy metals (Pb, Zn, Cu, Cd, Mn, and Fe) and aluminum in the waters connected with mining and associated deposits (dumps, tailings) reduce water quality. In the mining area, Ca and SO$_4$ are predominant cation and anion. The mining water is Ca-SO$_4$ type and is enriched in heavy metals resulted from the weathering of sulfide minerals. This mine drainage water is weakly acid or neutral (pH; 6.5-7.1) because of neutralizing effect by other alkali and alkaline earth elements. The effluent from the mine adit is also weakly acid or neutral, and contains elevated concentrations of most elements due to reactions with ore and gangue minerals in the deposit. The concentration of ions in the Backun mining water is high in the mine adit drainage water and steeply decreased award to down stream. Buffering process can be reasonably considered as a partial natural control of pollution, since the ion concentration becomes lower and the pH value becomes neutralized. In order to evaluate mobility and bioavailability of metals, sequential extraction was used for stream sediments into five operationally defined groups: exchangeable, bound to carbonates, bound to FeMn oxide, bound to organic matter, and residual. The residual fraction was the most abundant pool for Cu(2l-92%), Zn(28-89%) and Pb(23-94%). Almost sediments are low concentrated with Cd(2.7-52.8 mg/kg) than any other elements. But Cd dominate with non stable fraction (68-97%). Upper stream sediments are contaminated with Pb, and down area sediments are enriched with Zn. It is indicate high mobility of Zn and Cd.

• Economic and Environmental Geology
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• v.50 no.4
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• pp.257-266
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• 2017

Batch experiments were performed to develop the method for the pH reduction of recycled aggregate by using $scCO_2$ (supercritical $CO_2$), maintaining the pH of extraction water below 9.8. Three different aggregate types from a domestic company were used for the $scCO_2$-water-recycled aggregate reaction to investigate the low pH maintenance of aggregate during the reaction. Thirty five gram of recycled aggregate sample was mixed with 70 mL of distilled water in a Teflon beaker, which was fixed in a high pressurized stainless steel cell (150 mL of capacity). The inside of the cell was pressurized to 100 bar and each cell was located in an oven at $50^{\circ}C$ for 50 days and the pH and ion concentrations of water in the cell were measured at a different reaction time interval. The XRD and SEM-EDS analyses for the aggregate before and after the reaction were performed to identify the mineralogical change during the reaction. The extraction experiment for the aggregate was also conducted to investigate the pH change of extracted water by the $scCO_2$ treatment. The pH of the recycled aggregate without the $scCO_2$ treatment maintained over 12, but its pH dramatically decreased to below 7 after 1 hour reaction and maintained below 8 for 50 day reaction. Concentration of $Ca^{2+}$, $Si^{4+}$, $Mg^{2+}$ and $Na^+$ increased in water due to the $scCO_2$-water-recycled aggregate reaction and lots of secondary precipitates such as calcite, amorphous silicate, and hydroxide minerals were found by XRD and SEM-EDS analyses. The pH of extracted water from the recycled aggregates without the $scCO_2$ treatment maintained over 12, but the pH of extracted water with the $scCO_2$ treatment kept below 9 of pH for both of 50 day and 1 day treatment, suggesting that the recycled aggregate with the $scCO_2$ treatment can be reused in real construction sites.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.434-442
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• 2017

The UV light in sunlight breaks down the chemical bonds in a polyolefin polymer through a process called photodegradation, ultimately causing cracking, chalking, colour changes, and loss of physical properties such as impact strength, tensile strength, elongation, and others. UV absorbers are used to prevent or terminate the oxidation of plastics by UV light. They are receptive to UV radiation and dissipate the energy harmlessly as heat. Benzotriazoles and benzophenones are used mainly in polyolefins such as polyethylene and polypropylene. In this study, we have developed a method for the analysis of 12 UV absorbers, which are Uvinul 3000, Cyasorb UV 24, Uvinul 3040, Tinuvin 312 and P, Seesorb 202, Chimassorb 81, Tinuvin 329, 234, 326, 328 and 327, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The UV absorbers in food simulants were determined by reversed-phase high performance liquid chromatograph-ultraviolet detector with 310 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.049~0.370 mg/L), and limits of quantification (0.149~1.120 mg/L). The recoveries of UV absorbers spiked to four food simulants ranged from 70.05% to 110.13%. The developed method would be used as a reliable tool to determine concentrations of the migrated UV absorbers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.411-420
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• 2007

This study was conducted to increase sweetpotato utilization and to determine the vegetative value of sweetpotato tips by investigating the phenolic compounds, antioxidative effect in oil, electron donating ability, nitrite scavenging effect and ACE inhibition activities. The phenolic compounds present in sweetpotato tips are the gallic, chlorogenic, gentisic, caffeic, couramic and ferulic acid, which are 16-122 times higher compared to other vegetables such as spinach, soybean sprout, and perilla leaves. In each solvent extract, the total phenolic compounds(175.8 mg/g) was composed of 55% EtOAc extraction and 39% BuOH extract, respectively. The results of induction period using the Rancimat method showed that the antioxidant activity of SP tips was higher than the tocopherol or BHT. The relative levels of each solvent extract in SP tips were as follows: EtOAc>BHT>BuOH>Tocopherol>Water>$CHCl_3$>Hexane. The peroxide value was measured every 5 days for 25 days during storage and results showed that the peroxide value, the tips, tuberous root and tocopherol were lower compared to spinach, soybean sprout and perilla leaves. Nitrite scavenging effects were excellent in sweetpotato tips, perilla leaves and soybean sprout, especially, inhibition rate of perilla leaves(72%) were superior to the others. In process of solvent extraction, activity of BuOH and water extractions were the best. ACE inhibition activity in sweetpotato tips was 1.5 times higher than in tuberous roots and $1.9{\sim}3.7$ times higher than in spinach, soybean sprout, perilla leaves.

• Journal of Life Science
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• v.24 no.8
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• pp.865-872
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• 2014

In this study, ethanol and hot water extracts of lees from Korean traditional wine (J-B, J-S, J-Y, J-H, and J-W) were prepared, and their effects on blood coagulation, platelet aggregation, and hemolysis of human red blood cells (hRBCs) were investigated to develop functional food ingredients from lees. The pH and brix of the lees ranged from 3.90 to 4.29 and 5.0 to $27.0^{\circ}$, respectively, and there was a huge difference in the water and ethanol content among the lees. The nuruk and additives used affected the color and physicochemical properties of lees. The J-W takju made from only rice and traditional nuruk, which has $13^{\circ}$ brix and 1.8% of alcohol, has potential as functional food ingredient. With regard to the extraction yields of lees, higher yields were obtained from J-H, which contains different medicinal plants, in ethanol, followed by J-W, J-B, J-S, and J-Y. Higher extraction yields of lees were obtained from J-S in hot water, followed by J-B, J-W, J-H, and J-Y, respectively. The ethanol extract of J-H and the hot water extract of J-Y had the highest contents of total polyphenol and total flavonoids among the lees extracts. The 10 lees extracts did not show hemolysis activity against hRBCs up to 5 mg/ml. In an anticoagulation activity assay, the ethanol extracts of three yakju lees (J-B, J-S, and J-Y) and the hot water extract of J-W inhibited thrombin activity, whereas the hot water extract of J-B, J-S, and J-H inhibited blood coagulation factors. In an antiplatelet aggregation activity assay, only the J-W takju lees showed significant inhibition activity. Our results suggest that lees from traditional wine had high potential as a novel antithrombosis agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1610-1616
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• 2016

This study aimed to establish an optimal extraction process and high performance liquid chromatography-ultraviolet (HPLC-UV) analytical method for determination of 3,5-dicaffeoylquinic acid (3,5-DCQA) as a part of materials standardization for the development of a xanthine oxidase inhibitor as a health functional food. The quantitative determination method of 3,5-DCQA as a marker compound was optimized by HPLC analysis using a Luna RP-18 column, and the correlation coefficient for the calibration curve showed good linearity of more than 0.9999 using a gradient eluent of water (1% acetic acid) and methanol as the mobile phase at a flow rate of 1.0 mL/min and a detection wavelength of 320 nm. The HPLC-UV method was applied successfully to quantification of the marker compound (3,5-DCQA) in Aster glehni extracts after validation of the method with linearity, accuracy, and precision. Ethanolic extracts of A. glehni (AGEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 30, 50, 70, and 80% ethanol for 3, 4, 5, and 6 h, respectively. Among AGEs, 70% AGE at $70^{\circ}C$ showed the highest content of 3,5-DCQA of $52.59{\pm}3.45mg/100g$ A. glehni. Furthermore, AGEs were analyzed for their inhibitory activities on uric acid production by the xanthine/xanthine oxidase system. The 70% AGE at $70^{\circ}C$ showed the most potent inhibitory activity with $IC_{50}$ values of $77.01{\pm}3.13{\sim}89.96{\pm}3.08{\mu}g/mL$. The results suggest that standardization of 3,5-DCQA in AGEs using HPLC-UV analysis would be an acceptable method for the development of health functional foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.594-600
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• 2009

Quality characteristics of white lotus leaf tea (LLT) fermented with or without mycelial Paecilomyces japonica were investigated. Extraction yield and browning index of hot water extract from non fermented and fermented LLTs were higher than those of ethanol extract (p<0.05). In all LLTs, nutritional components such as total free sugar, free amino acids and minerals of hot water extracts were higher than those of ethanol extracts except for total organic acids (p<0.05). Contents of total free sugar and organic acids were markedly increased through fermentation process of mycelial Paecilomyces japonica. in the same solvent extracts (p<0.05). Contents of most taste components of fermented LLT were increased by mycelial solid fermentation (p<0.05), but total free amino acids of two extracts were decreased in the range of $37.1{\sim}67.2%$ as compared to non-fermented LLT. Fifty-nine volatile compounds were identified by GC and GC-MS, including 11 aldehydes, 14 alcohols, 11 ketones, 11 hydrocarbones and 12 acids. Aldehyde and ketone compounds were more identified in fermented LLT than in non-fermented LLT being abundant alcohol compounds by simultaneous steam distillation and extraction. The most abundant compounds of LLT identified in this study were curcumene followed by 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol and cyclohexen. Main compounds of fermented LLT were 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol, butanoic acid, furfural, benzaldehyde, hexanoic acid and 2(3H)-furanone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.579-585
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• 2015

The objective of this study was to investigate the quality characteristics of coffee soaked in Morus bombycis extract. Green coffee beans were soaked in M. bombycis extract for 2, 4, and 6 hours (sample codes: 2H, 4H, and 6H) at $4^{\circ}C$. Soaked green beans were dried and roasted for coffee extraction. Two controls, roasted with the same amount of heat (C1) and showed the same weight after roasting (C2), were used. Physicochemical characteristics (pH, total acidity, color, browning index, and total soluble solids), DPPH free radical scavenging activity (DPPH), ferric-reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total polyphenol content (TPC), and total flavonoid content (TFC) were investigated. Lower pH and higher total acidity were observed in 2H, 4H, and 6H (P<0.05), supporting evidence of sour taste. There were significant differences in DPPH between the controls (45.51~47.02%) and samples (50.67~55.25%, P<0.05), although 2H and 6H did not show significantly higher DPPH than the controls. 2H, 4H, and 6H showed significantly higher FRAP values ($0.320{\sim}0.331\;FeSO_4{\cdot}7H_2O\;mM\;FeSO_4/g$) than controls ($0.265{\sim}0.271\;mM\;FeSO_4/g$). ORAC values of samples [1,062.86~1,153.68 mM trolox equivalent (TE)/g] were significantly higher than those of controls (689.40~942.12 mM TE/g). 2H, 4H, and 6H showed significantly higher TPC [24.27~26.07 mg gallic acid equivalent (GAE)/g] and TFC [3.75~4.28 mg quercetin equivalent (QE)/g] than controls (19.79~22.77 mg GAE/g and 1.07~1.95 mg QE/g, respectively) (P<0.05). M. bombycis extracts soaked into green coffee beans showed polyphenol compounds from green coffee beans. Consumer acceptance of 4H (5.12) was the highest, followed by C2 (4.92). C1 (4.14) showed the lowest consumer acceptance. Consumers were segmented into two groups, those who preferred M. bombycis extract-soaked coffee (approximately 61%) and controls (approximately 39%).

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.264-270
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• 2013

Imidacloprid is a systemic insecticide which act as an insect neurotoxin. It used for control of pest such as aphids and other sucking insects in fruits and vegetables. Systemic pesticides move inside a crop following absorption by the plant, and these were converted into a variety of metabolites. Sometimes these metabolites make a problem about safety of agricultural products. So a simultaneous determination method of pesticide and its metabolites is needed, to monitor their presence in agricultural product and study on the fate of pesticide in a plant. This study's aim is to investigate simultaneous analysis method of imidacloprid and its metabolites, imidacloprid guanidine, imidacloprid olefin, imidacloprid urea, and 6-chloronicotinic acid in red pepper using QuEChERS method and LC-MS/MS systems. QuEChERS method was modifed beacuase $MgSO_4$ salts decreased the recoveries of 6-chloronicotinic acid in extraction procedure. Imidacloprid and its metabolites were extracted by acetonitrile with 1% glacial acetic acid and the extracts were purified through QuEChERS with primary secondary amine (PSA) and $C_{18}$ and analyzed with LC-MS/MS in ESI positive mode. Standard calibration curves were made by matrix matched standards and their correlation coefficients were higher than 0.999. Recovery studies were carried out on spiked pepper blank sample at four concentration levels (0.01, 0.04 and 0.1, 0.4 mg/kg). The average recoveries of imidacloprid and its metabolites were in the range of 70~120% with < 20% RSD. This result indicated that the method using QuEChERS and LC-MS/MS was suitable for the simultaneous determination of imidacloprid and its metabolites in red pepper.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.314-334
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• 2013

This study explored an efficient modified Quick, Easy, Cheap, Effective, Rugged and safe (QuEChERS) method combined with liquid chromatography-electrospray ionization with tandem mass spectrometric detection for the analysis of residues of 76 pesticides in brown rice, barley and corn including acidic sulfonylurea herbicides. Formic acid (1%) acid in acetonitrile and dispersive solid phase extractions used for extraction of pesticides and clean-up of the extract respectively. Two fortified spikes at 50 and 200 ng $g^{-1}$ levels were performed for recovery test. Mean recoveries of majority of pesticides at two spike levels ranged from 73.2 to 132.2, 80.9 to 136.8, 66.6 to 143.5 for brown rice, barley and corn respectively with standard error (CV) less than 10%. Good linearity of calibration curves were achieved with $R^2$ > 0.9907 within the observed concentration ranged. The modified method also provided satisfactory results for sulfonylurea herbicides. The method was applied to the determination of residues of target pesticides in real samples. A total of 26 pesticides in 36 out of 98 tasted samples were observed. The highest concentration was observed for tricyclazole at 1.17 mg $kg^{-1}$ in brown rice. This pesticide in two brown rice samples exceeded their MRLs regulated for rice in republic of Korea. Except tricyclazole none of the observed pesticides' concentration was higher than their MRLs. The results reveal that the method is effectively applicable to routine analysis of residues of target pesticides in brown rice, barley and corn.