• Journal of the Korean Society of Food Culture
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• v.10 no.1
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• pp.11-17
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• 1995

The changes in life style these days appear in many ways. Many housewives turn away from home preparation of the time consuming traditional foods, such as Andong Sikhe. The importance, however, of succeeding the traditional cuisines is getting appreciated widely now a days. A traditional Andong Sikhe in Korea, was prepared and fermented at $5^{\circ}C$ in order to analyze the taste and flavor compounds. Major flavor components were identified as camphene, sabinene, 1-(1,5-dimethyl-4-hexyl)-4-methyl-benzene, ${\alpha}-zingibirene$, farnesene, 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol, ${\beta}-sesquiphellandrene$, calalene, tetradecanoic acid, hexadecanoic acid and 9,12-octadecanoic acid by GC and GC/MS. Lactic acid and increased from 0.49 mg/100 g in the initial stage to 19.37 mg/100 g at the 6 days of storage. The pH of product decresed to 3.7 from 5.4 after the 6 days of storage but the total acidty reached to 0.41% during fermentation and storage at $5^{\circ}C$.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.711-717
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• 2005

A magenta azomethine dye(D) was synthesized from the reaction of 3-methyl-1-phenyl-2-pyrazoline-5-one with N,N-diethyl-1,4-phenylenediamine. The magenta azomethine dye was identified on the basis of elemental analysis, $^{13}C-NMR$, infrared, and GC/MS studies. The magenta azomethine dye was decomposed in a basic solution. Rate constants of the fading reaction of magenta azomethine dye in ethanol-water solvent were measured spectrophoto­metrically at 540 nm. Reaction rate was increased with the increase of $[OH\^{-}]\;and\;[H\_{2}O]$ in the region of $[H_{2}O]=11\~40\;M$. The reaction was governed by the following rate law. -d[D]/dt = $\{k_o\;+\;k_{OH}[OH^-][H_{2O}]\}[D]$ A possible mechanism consistent with the empirical rate law has been proposed.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.183-187
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• 1997

The analytical conditions of 1,3-dichloro-2-propanol (DCP) and 3-chloro-1,2-propanediol (MCPD) by solid phase extraction were optimized to improve recovery. Selected-ion monitoring technique which was used for GC-MS analysis of both compounds gave substantially higher sensitivity. The detection limits of DCP and MCPD were 25 and 50 ppb, respectively. The effects of extraction column type, elution solvent and salt concentration on recovery were examined. A normal phase column was better than a reverse phase column in solid phase extraction of DCP and MCPD. It was explained in terms of polarity relationship of solvent-solute-solid phase. A maximum recovery was obtained at the salt concentration of 20% (w/v). Water-immiscible and chloropropanol-soluble solvents such as chloroform, diethyl ether, hexane and ethyl acetate were tested for elution solvent. Hexane and ethyl acetate were the most suitable solvents for the extraction of DCP and MCPD, respectively. High recovery better than 95% was obtained with the selected solvents.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.237-248
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• 2006

Forty one compounds such as ester, sulfonyl ester, carbamate, ether and phosphoyl ester derivatives of thymol(I) and carvacrol(II) were synthesized. These derivatives were identified by IR, GC/MS and $^1H$-NMR spectra. Their antifungal activities were tested against various plant pathogenicfugi. Among them, several compounds were showed potent in vivo antifungal activities. The selected compounds showing in vitro antifungal activities were tested in vivo antifungal activities aganint 5 plant diseases such as rice blast, rice sheath blight, tomato late blight, cucumber anthracnose, and cucumber gray mold. As a result, 2-isopropyl-5-methylphenylacetate(I-1a) effectively suppressed the development cucumber gray mold and rice blast. Methyl(2-isopropyl-5-methylphenoxy)acetate(I-6d) and ethyl 4-(5-methyl-2-isopopylphenoxy)crotonate(I-7d) also showed potent in vivo antifungal actively againt rice sheath blight and tomato late blight, respectively.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.66-78
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• 2019

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.583-590
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• 2012

The HF (Hollow fiber) extraction method was optimized to analysis seven species of pesticides in aqueous sample and analyzing samples by GC/MS. Hollow fiber extraction showed good efficiency when it was conducted under these conditions: organic solvent was toluene and agitation speed was 1200 rpm. The 15% concentration of NaCl was optimized when it was experimented between 5% and 25%. The equilibrium time was determined at 15 minutes. The pH 5 showed the best effect on the extraction efficiency. The linearities of calibration curves of seven species were good with correlation of regression ($r^2$) over 0.995 when they were experimented over a concentration range of $5{\mu}g/L$ to $50{\mu}g/L$. The analytical data exhibited the detection of limits (LODs) range of $0.37{\mu}g/L$ to $1.23{\mu}g/L$ and the limit of quantification (LOQs) range of $1.19{\mu}g/L$ to $3.91{\mu}g/L$. The optimized HF-LPME extraction method provides a simple and effective preparation and requires small amount of organic solvents and samples compared to conventional pre-treatment methods.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.425-431
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• 2014

In this study, the volatile compounds in 24 commercial Korean black raspberry wines were isolated by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 43 volatile components, including 15 esters, 12 terpenes, 7 alcohols, 4 acids, 3 ketones, and 2 aldehydes, were identified. Ethyl esters and alcohols such as ethyl acetate, ethyl octanoate, isoamyl alcohol, and phenethyl alcohol were the most represented groups among the quantified volatiles. In particular, various terpenes such as DL-limonene, linalool, alpha-terpineol, and myrtenol were identified. The differences in volatile components among the 24 black raspberry wines and possible sample grouping were examined by applying principal component analyses to the GC-MS data sets. The first and second principal components explained 43.9% of the total variation across the samples. No apparent sample groupings were observed according to manufacturing locations. The samples KU, BH, SR, and MO showed higher overall levels in the concentrations of terpenes originating from black raspberry, while other samples such as BB and HB, showed higher in ethyl ester and alcohol contents produced by yeast fermentation, respectively.

• KSBB Journal
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• v.9 no.5
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• pp.469-474
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• 1994

The purpose of the work was to evaluate the feasibility of a biological treatment process for the phenoxy alkanoic herbicide 2,4-D(2,4-dichlorophenoxyacetic acid) as a commercial pesticide. The phenoxy herbicide was 2,4-D amine salts which contained 40%(vol/vol) 2,4-D and 60%(vol/vol) solvent. A microbial consortium has been derived by enrichment with 2,4-D. The consortium utilized 2,4-D as the sole source of carbon and energy. Optimal pH on the 2,4-D degradation was 7.0 in this experiment. As concentrations of 2,4-D were increased, the degradation by microbial consontium became inhibited. The amendment with yeast extract and ascorbic acid accelerated the degradation of 2,4-D. High performance liquid chromatography methodology was used to measure 2,4-D and it also resolved 2,4-DCP(2,4-dichlorophenol), the corresponding phenol as intermediate. Gas chromatography-mass spectrometry was used for preliminary identification of the intermediate 2,4-DCP. UV scans of spent cultures showed that the maximum absorption of 2,4-D at the wavelength of 283 nm was decreased toward the end of incubation, but the consortium displayed no detectable spectral changes or peak shifts in the UV absorbance.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.393-398
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• 2020

The blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is an emerging pest on cultivated blueberries in Korea. To develop a sensitive tool for monitoring this pest in blueberry orchards, we compared the attractiveness of host plant volatiles and sex pheromone to D. oxycoccana adults. We performed gas chromatography-mass spectrometry (GC-MS) analysis of solid-phase microextraction (SPME)-collected volatiles that were released from blueberry ('Darrow' cultivar). The analysis revealed two major volatiles, cinnamaldehyde and cinnamyl alcohol from flowers; and three major volatiles, β-caryophyllene, germacrene D, and α-farnesene from shoots and young fruits. In field tests conducted in Gunsan, Korea in 2019, commercialized cinnamaldehyde, cinnamyl alcohol, β-caryophyllene, and α-farnesene, used singly or in quaternary combination, were unattractive to the blueberry gall midge. However, traps baited with the known sex pheromone (2R,14R)-2,14-diacetoxyheptadecane attracted significantly more males than the treatments with plant volatiles or the control. No synergistic effect was observed between sex pheromone and plant volatiles. Male D. oxycoccana were captured in the pheromone traps from May to August, with three peaks in mid-May, late June, and late July in Gunsan blueberry fields in 2020.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.25-30
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• 2010

This paper describes a simultaneous method for the determination of two aminoglycosides (neomycin and gentamicin) using solid phase extraction followed by liquid chromatograph-mass spectrometry. The extract was applied to an WCX and HLB solid phase extraction cartridge. The cartridges were washed with water and methanol, and analytes were eluted with TCA buffer-acetonitrile mixture. The aminoglycosides were separated by ion-pairing reversed phase mode prior to ESI-LC/MS. Under the conditions applied neomycin was almost separated from all the gentamicin compounds. No interfering peaks from endogenous compounds of matrix were noted at the elution position of the analytes. Recoveries of neomycin fortified at levels of 0.25, 0.5, 1.0 and 2.0 mg/kg seafood samples ranged from 92 to 115%. Recoveries of gentamycin fortified at levels of 0.05, 0.1, 0.2, 0.4 mg/kg seafood samples ranged from 99 to 116%. Method detection limits in four seafood sample matrices were between 0.002 and 0.033 mg/kg.