• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.370-374
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• 1989

This study was conducted to examine the effects of salt concentrations (1,2 and 37)) and storage periods on the characteristics of Kakdugi (Korea seasoned pickles of cubed radish roots) stored at $20^{\circ}C$. The sensory characteristics, pH, titratable acidity, non-volatile organic acids were measured. The results of sensory evaluation on Kakdugi containing 1,2 or 30% sodium chloride stored for 4 or 8 days indicated that there were significant differences among them expecially ill firmness, crispness and salty taste. As storage period increased, titratable acidity, sour taste, non-volatile organic acid contents of the samples increased. The changes were greater in Kakdugi with 2% sodium chloride. Major non-volatile organic acids were identified as lactic acid, citric acid and succinic acid. The sour taste of Kakdugi was closely related to the contents of non-volatile organic acid and titratable acidity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.227-234
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• 1985

The present study was carried out for making clear the organic acids composition of some shellfishes and their boiled-dried products. Three species of shellfish such as top shell, hard clam and abalone were chosen as the experimental samples and analysed for their nonvolatile organic acids composition by gas liquid chromatography (GLC). Eight kinds of nonvolatile organic acid were identified in raw and boiled-dried top shell, major ones were succinic, malic and pyroglutamic acid. Out of nine kinds of nonvolatile acid was determined in raw and boiled-dried of hard clam, abundant ones were succinic, lactic and malic acid, And seven kinds of nonvolatile organic acid were detected in boiled-dried abalone while eight kinds in raw sample, abundant ones were succinic, lactic and pyroglutamic acid, respectively. In all samples, the total amount of nonvolatile organic acid was the most abundant in hard clam while the least in abalone, and the content of succinic acid was appeared as the most abundant one. In dried samples, the total amount of the nonvolatile organic acid was determined to be about half-decrease after the boiled-dried treatment of the raw samples, of which abalone showed the highest decreasing을 rate whereas hard clam was the lowest. In general, the decreasing rate of each acid was the higher in fumaric, malic and citric acid than in maleic, oxalic and succinic acid.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.2
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• pp.147-152
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• 2008

Due to the development and expansion of industries and medical standards, the number of workers who handle organic solvents within hospitals is increasing. The authors in this study intended to investigate the actual conditions of the handling of the solvents and to encourage the recognition that the exposure to such solvents may be possible because of insensitivity to safety. In order to investigate the actual conditions of exposure of workers within hospitals, the experimental group included the three sections (Pathology department, Central Supply Room, and Operating Room), which handle organic solvents most frequently. Meanwhile, university interns were selected to be the control group. This study was conducted between May 1 to May 30, 2007, and urine was taken as samples. Hippuric acid, mandelic acid, methylhippuric acid, and phenylglyoxylic acid were analyzed through gas chromatography, and a total of 52 subjects of the experimental and the control groups were performed of the analysis. As for the results of the analysis of the experimental group, the exposure to benzene was $42.27{\pm}3.70mg/g$ creatinine, that of xylene was $1.30{\pm}0.18g/g$ creatinine, and that of toluene was $2.36{\pm}0.24g/g$ creatinine. Meanwhile, the results of the analysis of the control group showed that the exposure to benzene was $15.54{\pm}2.85mg/g$ creatinine, that of xylene was $0.52{\pm}0.02g/g$ creatinine, and that of toluene was $0.85{\pm}0.20g/g$ creatinine. The amount of exposure to benzene, xylene, and toluene was shown to be under the maximum permitted level, but as for Pathology department, it was required to educate on working conditions, to educate workers on prevention management about their health, and to install fume hood and exhaust system to improve the environments.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.74-77
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• 2012

Organic acid (OA) profiling analysis was performed in culture media from Lactobacillus pentosus K34 (L. pentosus K34) and Pediococcus lolli PL24 (P. lolli PL24) by gas chromatography-mass spectrometry (GC-MS) following methoxime/tert-butyldimethylsilyl derivatives. 12 OAs were positively identified in culture media. Most of OA levels from L. pentosus K34 of hetero lactic fermentation were found to be higher when compared with those from P. lolli PL24 of homo lactic fermentation, which may explain different OA metabolism in each strain. In addition, the distorted dodecagonal star patterns were readily distinguishable, and the characteristics of each strain were well represented. The present study demonstrates that the OA metabolic profiling method by GC-MS combined with star pattern recognition is useful for the monitoring study of characteristic OA metabolism in various microorganisms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1022-1027
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• 2004

The monacolin K content was determined to investigate the stability of monacolin K from red yeast rice after heating (20∼8$0^{\circ}C$), adjusting the pH (2∼8) by adding 3 N HCl or 3 N NaOH, adding the organic acid (6.0% acetic acid, 0.6% citric acid, 1.5% lactic acid) to pH 4.0 and adding the water (0∼80%). And the monacolin K was isolated from red yeast rice by conducting open column chromatography using neutral aluminum oxide. As a result, the stability of monacolin K decreased with increasing the temperature. The stability for pH was in the order of the unadjusted pH (pH 5.9)>8>4 and pH 2>10. The stability for organic acid was high in the order of lactic acid>citric acid>acetic acid, and the stability of monacolin K under acid was different according to the acid type. The degradation rate of monacolin K increased with increasing the water content. Moreover monacolin K was able to isolate from red and pink pigments as well as the other noncoloric compounds in red yeast rice. The yield of monacolin K was found to be 70%.

• Korean Journal of Microbiology
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• v.23 no.4
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• pp.241-247
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• 1985

The objectives of this study were to isolate and identify ninhydrin positive substande(s) produced in the culture broth of Pseudomonas fluorescens. It was found that the NPS could stimulate bioconversion of furfural into furoic acid. In order to isolate the NPS from the culture broth, cell free filtrate was subjected to ion-exchange chromatography, gel-permeation and finally to cellulose column chromatography. The purified NPS was white amorphous power and very soluble in water, slightly soluble in methanol and very insoluble in organic solvents. UV, and IR absorption spectra. $^H$ and $^{13}C-NMR$ were measured in order to identify the chemical structure of the NPS.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.2
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• pp.51-66
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• 1986

Volatile aroma components, non-volatile organic acids in lamina and stems of flue-cured(NC 2326) and burley ( Burley 21) were analyzed by gas chromatography and mass spectrometry, respectively. Then compositional differences of these components between lamina and stems were discussed. The contents of volatile components were higher in flue-cured than in burley tobacco, and it was also higher in lamina then in stem. The major aroma components in lamina were neophytadiene , nicotine, solanone and benzyl alcohol but those in stems were palmitic acid, neophytadiene, nicotine, solanone and phenyl ethyl acetate. On the other hand, the contents of non-volatile organic acids were higher in burley than in flue-cured tobacco, and these values of burley tobacco were higher in lamina than in stem but flue-cured tobacco were higher in stem than in lamina. The major acids in all the above four tabacco samples were malic, citric, oxalic and linolenic acid.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.411-415
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• 1990

The dabsylation of amino acids has been applied to resolve their optical isomers with the use of chiral mobile phase in high performance liquid chromatography. The dabsyl amino acids were successfully separated on reversed phase column($C_{18}$) by adding a chiral L-benzylproline-Cu(II) chelate to the mobile phase. The separation selectivity of the dabsyl amino acid enantiomers was not less than that of dansyl amino acids. The retention order of the dabsyl amino acid enantiomers was as those of the dansyl amino acid enantiomers except dabsyl threonine. The optical selectivity of the dabsyl amino acids increase with pH of the mobile phase and concentration of the chelate, but slightly decreases with concentration of buffer and organic solvent composition. However serine, methionine, valine, and leucine showed a slight decrease in the optical selectivity with increase in pH. The retention times of the dabsyl amino acids decreases with increasing pH and acetonitrile concentration but increases with the concentration of the chiral chelate added. The mechanism of the optical resolution is based on a stereospecific interaction including a intramolecular hydrophobic effect and SN-2 reactivity of the ligand exchange chromatography.It is advantageous to detect absorption at 436 nm, which is less interferent them the other detection systems. The derivatized dabsyl amino acids are stable for a month.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.887-896
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• 2015

To develop environment-friendly agricultural products with anti-microbial activity against Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Usnea longissima was extracted by methanol and its extract was fractionated into several solvent fractions. The chloroform fraction, which showed the highest antimicrobial activity, was separated by silica gel-column chromatography and obtained into nine group subfractions. The nine group fractions were searched the antifungal activities by bioassay. The most active No. 3 subfraction was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to database of Wiley library. As a result, Usnic acid was identified as main compounds. In conclusion, Usnic acid isolated from Usnea longissima was antimicrobial chemical against Sclerotinia sclerotiorum as a pathogen of sclerotium disease.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.269-276
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• 2015

This study investigated the influence of characteristics of natural organic matter (NOM) on the formation of disinfection by-products (DBPs), and proposed the control strategies of DBPs formation in a drinking water treatment plant using lake water in Gyeongsangbuk-do. The fluorescence excitation-emission matrix analysis results revealed that the origins of NOM in raw waters to the plant were a mixture of terrestrial and microbial sources. Molecular size distributions and removals of NOM fractions were evaluated with a liquid chromatography-organic carbon detector (LC-OCD) analysis. Humic substances and low molecular weight organics were dominant fractions of NOM in the raw water. High molecular weight organics were relatively easier to remove through coagulation/precipitation than low molecular weight organics. The concentrations of DBPs formed by pre-chlorination increased through the treatment processes in regular sequence due to longer reaction time. Chloroform (74%) accounts for the largest part of trihalomethanes, followed by bromodichloromethane (22%) and dibromochloromethane (4%). Dichloroacetic acid (50%) and trichloroacetic acid (48%) were dominant species of haloacetic acids, and brominated species such as dibromoacetic acid (2%) were minimal or none. Dichloroacetonitrile (60%) accounts for the largest part of haloacetonitriles, followed by bromochloroacetonitrile (30%) and dibromoacetonitrile (10%). The formation of DBPs were reduced by 16~44% as dosages of pre-chlorine decreased. Dosages of pre-chlorine was more contributing to DBPs formation than variations of dissolved organic contents or water temperature.