• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.366-372
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• 2001

Volatile flavor components in the mash of Takjus prepared by using Aspergillus oryzae nuruk were identified by using Gas Chromatography and Gas Chromatography-Mass Spectrometry. Twenty-four esters, 21 alcohols, 10 acids, 9 aldehydes and 4 others were found in the mash of Takju. Thirty six components including 13 esters and 12 alcohols were detected in the beginning of fermentation. Twenty nine components were more detected after second day of fermentation and 68 components were detected after 12 days of fermentation. Thirty five flavor components including 12 alcohols such as ethanol, 2-methyl-1-propanol, 3-methyl-1-butanol and benzeneethanol, 13 esters such as ethyl acetate, ethyl caprylate, ethyl butyrate and isoamyl acetate, 4 aldehydes and 6 acids were usually detected in the fermentation process. Ethanol was predominantly found in the range of $79.86{\sim}89.54%$ as a major component by using relative peak area. 3-Methyl-1-butanol, ethyl caprylate and benzeneethanol were some of the major volatile components through the fermentation respectively. Peak area of 2-methyl-1-propanol, 1-hexanol, 1-dodecanol, ethyl acetate, monoethyl butanoate, acetic acid and isobutylaldehyde among the same group were higher than other components depending upon fermentation time.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.380-386
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• 1995

An attempt was made to determine the effects of drying methods including shady air drying, presteamed and shady air drying, microwave drying, and freeze drying on the volatile flavor components with Commelina communis L.. Essential oils from the samples were isolated by simultaneous steam distillation-extraction(SDE) method using diethyl ether as solvent. Concentrated samples were analyzed by gas chromatography(GC) and combined gas chromatography-mass spectrometry(GC-MS). Respective 29, 47, 36, and 24 volatile flavor components were identified in shady air dried samples, presteamed and shady air dried samples, microwave dried samples, and freeze dried samples. The kinds and amounts of volatile flavor components were evidently depended upon the drying methods. 6,10,14-trimethylpentadecanone was regarded as the most abundant component in shady air dried samples, 6,10,14-trimethyl-2-pentadecanone in presteamed and shady air dried samples, neophytadiene in microwave dried samples, and ethyl acetate in freeze dried samples.

• Journal of Conservation Science
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• v.33 no.1
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• pp.51-59
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• 2017

Lacquer has been used as a natural paint or adhesive in Korea since 2nd century B.C. It has been found to have been used as an adhesive as mentioned in old records and as seen in excavated relics, It was also mixed with flour, animal glue, or fish glue to produce lacquer adhesives. Qualitative analysis and evaluation of the applicability of lacquer and additives was performed in this study. The results of EGA analysis for lacquer additives confirmed that the pyrolysis temperature of lacquer, glucose glue, and animal glue. On the basis of this result, raw lacquer sample was checked that pyrolysis product that originated from urushiol side chain (R group). Components originating from glucose and amino acid were detected in glutinous rice paste and animal glue samples. In this study, the optimum pyrolysis temperature for each lacquer and additive mixture was determined from basic qualitative analysis data. By performing the qualitative analysis of each mixture, the applicability of this technique for analyzing real relics was evaluated.

• Journal of Environmental Health Sciences
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• v.28 no.1
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• pp.21-29
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• 2002

To identify and evaluate the dichlorobenzidine(DCB)-DNA adducts in liver cell and bladder epithelial cells by $^{32}$ P-postlabeling and GC/MS-SIM, we orally exposed the dichlorobenzidine(20mg/kh body wt./day) to male Sprague-Dawley rats(l85$\pm$10g) for 14 days. Two kinds of DCB-DNA adduct(A1 and A2) were found at the same site of thin layer chromatogram of $^{32}$ P-postlabeling method in liver cells and bladder epithelial cells. In liver cells, relative adduct labeling(RAL) $\times$ 10$^{12}$ of DCB-DNA adduct A1 were 34.1$\pm$3.71 and 69.9$\pm$5.02, that of adduct A2 were 74.1$\pm$10.1 and 105.1$\pm$10.1 on 10 and 14 days after treatment, respectively. And in bladder epithelia cells, RAL $\times$ 10$^{12}$ of DCB-DNA adduct A1 were 5.92$\pm$1.60 and 15.9$\pm$1.31, that of adduct A2 were 9.81$\pm$2.81 and 22.8$\pm$1.79 on 10 and 14 days after treatment, respectively. DCB metabolites formed DNA adducts were monoacetyl-dichlorobenzidine(acDCB) and diacetyl-dichlorobenzidine(di-acDCB), which was identify by gas chromatography/mass spectrometry-scan ionization mode(GC/MS-SIM), after hydrolysis of DCB-DNA adducts isolated from live cells and bladder epithelial cells. The base peak of acDCB were 252 and 294 m/z, and that of di-acDCB were 252, 294 and 336 m/z. In conclusion, the exposed DCB formed two kinds of DCB-DNA adduct, the proximate materials of that were acDCB and di-acDCB in liver and bladder epithelial cells. And the above GC/MS-SIM method was found the DCB-DNA adducts could be monitoring by gas chromatography.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.723-729
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• 2005

Volatile compounds of dropwort (Oenanthe javanica DC), crown daisy (Chrysanthemum coronarium L. var. spatiosum), and sesame (Sesamum indicum L.) were isolated by steam distillation under reduced pressure (DRP) and liquid-liquid continuous extraction (LLE). Aroma extracts of the plants were identified by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) and their antioxidant activities were evaluated in two different assays. The aroma extracts isolated from dropwort, crown daisy, and sesame inhibited the oxidation of hexanal by 25%, 95%, and 99%, respectively, for one month at the $500{\mu}g/mL$ level. They inhibited malonaldehyde formation from cod liver oil by 48%, 54%, and 29%, respectively, at the $500{\mu}g/mL$ level. Their antioxidant activities were comparable to those of the natural antioxidant, ${\alpha}-tocopherol$.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.157-163
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• 1988

The volatile compounds produced from the browning reaction of 0.5M DL-alanine and 0.5M D-glucose mixture using propylene glycol as a reaction medium were analysed by gas chromatography and gas chromatography-mass spectrometry and effects of temperature($100^{\circ}C,\;120^{\circ}C,\;140^{\circ}C$) and time(20min, 2hours) on the formation of volatile compounds were investigated. Browning reaction were rapidly increased as the reaction temperature and time increased. From methylene chloride extracts, twenty six compounds, including 7 alkyl pyrazines. 4 pyrroles, 3 furans, 1 furanone and 11 miscellaneous compounds were identified. The relative amounts of pyrazines, pyrroles and furans were markedly increased as reaction temperature and time increased. The results showed that caramel-like and burnt sugar-like aroma produced by alanine -glucose reaction must be mainly comprised of nitrogeneous heterocyclic such as pyrazines, pyrroles and oxygen heterocyclic compounds such as 2-hydroxy-3-methyl-2-cyclopenten-1-one and 2,5-dimethyl-4-hydroxy-3(2H)-furanone.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.332-338
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• 2012

A simple and sensitive analytical method was developed using gas chromatography with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) for determination of Picoxystrobin in agricultural products (apple, hulled rice, mushroom, pepper, soybean, and mandarin). Picoxystrobin residues were extracted with acetonitrile, partitioned with saline water, and then they were cleaned up on a florisil solid-phase extraction (SPE) cartridge to obtain an extract suitable for analysis by GC-ECD and GC-MS. The method was validated using 6 agricultural product samples spiked with Picoxystrobin at different concentration levels (0.02, 0.05 and 0.5 mg/L). Average recoveries of Picoxystrobin (using each concentration three replicates) ranged 64.0~98.3% with relative standard deviations less than 10%, calibration solutions concentration in the range 0.1~5 mg/L, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.02 mg/L, respectively. The result showed that the developed analytical method is suitable for Picoxystrobin determination in agricultural products.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.925-932
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• 2017

Changes in the metabolite profiles of Lactobacillus sakei and its growth media, based on different culture times (0, 6, 12, and 24 h), were investigated using gas chromatography-mass spectrometry (MS) and liquid chromatography-MS with partial least squares discriminant analysis, in order to understand the growth characteristics of this organism. Cell and media samples of L. sakei were significantly separated on PLS-DA score plots. Cell and media metabolites, including sugars, amino acids, and organic acids, were identified as major metabolites contributing to the difference among samples. The alteration of cell and media metabolites during cell growth was strongly associated with energy production. Glucose, fructose, carnitine, tryptophan, and malic acid in the growth media were used as primary energy sources during the initial growth stage, but after the exhaustion of these energy sources, L. sakei could utilize other sources such as trehalose, citric acid, and lysine in the cell. The change in the levels of these energy sources was inversely similar to the energy production, especially ATP. Based on these identified metabolites, the metabolomic pathway associated with energy production through lactic acid fermentation was proposed. Although further studies are required, these results suggest that MS-based metabolomic analysis might be a useful tool for understanding the growth characteristics of L. sakei, the most important bacterium associated with meat and vegetable fermentation, during growth.

• Analytical Science and Technology
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• v.13 no.2
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• pp.136-150
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• 2000

For the identification of unknown drugs in biological samples, we attempted rapid high performance thin layer chromatographic method which is sensitive and selective chromatographic analysis of high performance thin layer chromatography (HPTLC) with automated TLC sampler and ultra-violet (UV) scanner. We constructed HPTLC database (DB) on two hundred five drugs by using the data of Rf values and UV spectra (scan 200-360 nm) as well as gas chromatography/mass spectrometry (GC/MS) DB on ninety six drugs by using the data of relative retention time (RRT) on lidocain and mass spectra. After extracting drugs in biological sample by solid phase extraction (Clean Screen ZSDAU020), we applied them to HPTLC and GC/MS DB. Drugs, especially extracted from biological samples, showed good matching ratio to HPTLC DB and these drugs were confirmed by GC/MS. In conclusion, this DB system is thought to be very useful method for the screening of unknown drugs in biological samples.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.389-400
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• 2011

A high-performance liquid chromatographic (HPLC) method was developed to determine residues of phenothrin and silafluofen, known as synthetic pyrethroids, in agricultural commodities. Insecticide residues were extracted with acetone from representative samples of four crops which comprised rice, apple, pepper and cabbage. The extract was purified serially by liquid-liquid partition and Florisil column chromatography. For rice and pepper samples, acetonitrile/n-hexane partition was additionally adopted to remove nonpolar interferences. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate two phenothrin isomers and silafluofen from sample co-extractives. Intact parent compounds were sensitively detected by ultraviolet absorption at 226 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine phenothrin and silafluofen residues at 0.02 and 0.01 mg/kg, respectively. Mean recoveries of phenothrin and silafluofen from four crop samples fortified at three levels in triplicate were in the range of 82.4~109.8% and 83.7~109.8%, respectively. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types and spiking levels. A selected-ion monitoring (SIM) LC/mass spectrometry (MS) with electrospray ionization was provided to confirm the suspected residue of phenothrin, even though no sufficient ionization of silafluofen was obtained. Both phenothrin and silafluofen could be successfully confirmed by gas chromatography/MS SIM with electron impact at 70 eV. The proposed method is sensitive, repeatable and rapid enough to apply to officially routine inspection of agricultural products.