• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1053-1058
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• 1998

Volatile flavor compounds in salt fermented big eyed herring were analyzed by vacuum simultaneous distillation solvent extraction/gas chromatography/mass spectrometry/olfactometry and aroma extract dilution anlaysis. A total of 44 volatile compounds were detected by GC/O analysis. Of these, 23 were positively identified, and composed of aldehydes(7), esters(5), ketones(4), sulfur containing compounds (3), aromatic hydrocarbons(2), alcohol(1) and nitrogen containing compound(1). Predominant odorants (Log3FD$\geq$5) in sample were ethyl butanoate(bubble gum /sweet candy-like), 3 methylbutyl butanoate (almond /nutty), 1 octen 3 one(earthy/mushroom like), (E,E) 2,6 nonadienal(roasted wheat/grainy), dimethyl trisulfide(soy sauce /cooked cabbage like), 2 acetylpyrazine(nutty/baked potato like) and unidentified compound(RI=1867, seaweed like).

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1086-1091
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• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.930-940
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• 2012

A comparison of essential oils composition of Aster tataricus L. (gaemichwi), Ligularia fischeri (gomchwi), Solidago virga-aurea var. asiatica Nakai (miyeokchwi), and Aster scaber (chamchwi) was performed by gas chromatography and mass spectrometry for the identification of volatile flavor characteristics in chwi-namuls. The essential oils were extracted by the hydro distillation extraction method. One hundred volatile flavor components were identified from gaemichwi essential oil. ${\alpha}$-Pinene (11.5%) was the most abundant compound, followed by myrcene (8.9%) and ${\beta}$-pinene (7.5%). Ninety-one volatile flavor components were identified from the essential oil of gomchwi. Aromadendrene (14.8%) was the most abundant component, followed by ${\beta}$-caryophyllene (7.6%) and 1-methyl-4-(1-methylethylidene)-cyclohexene (7.3%). Ninety-five volatile flavor constituents were detected in the essential oil of miyeokchwi, moreover, spathulenol (15.7%) was the most abundant component. Ninety-six volatile flavor constituents were detected in the essential oil of chamchwi. Epi-bicyclosesquiphellandrene (21.9%) was the most abundant component, followed by ${\beta}$-caryophyllene (9.5%) and ${\delta}$-terpinene (8.9%). The essential oil composition of gaemichwi was characterized by a higher contents of pinenes. The essential oil composition of gomchwi can be easily distinguished by the percentage of aromadendrene. Spathulenol and epi-bicyclosesquiphellandrene were regarded as the characteristic odorants of miyeokchwi and chamchwi, respectively.

• Journal of Life Science
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• v.11 no.1
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• pp.35-42
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• 2001

Irradiation-induced volatile flavor compounds in irradiated (0, 1, 3, 5, 10 kGy) pork meats were analyzed by liquid liquid continuous extraction (LLCE) and gas chromatography/mass spectrometry (GC/MS) methods. One hundred nine volatile compounds were detected in irradiated pork meats. These compounds were mainly composed of hydrocarbons (42 compounds), aromatic compounds (39), aldehydes(9), ketones(5) and miscellaneous compounds (14). Among these, three volatile compounds, such as decene, 1,2,3,4,-tetrahydro-6-methylnaphthalene and 1,2,3,4-tetrahydro-dimethylnaphthalene were selected as irradiation-induced compounds comparing with irradiation dosages in irradiated pork meats. By the high correlation coefficient with the increment of irradiation dose, however, decene (r=0.93) was considered as marker compound for detecting irradiation dosage in fresh pork meats.

• Food Science and Preservation
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• v.7 no.1
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• pp.1-7
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• 2000

To develop natural antimicrobial agents for keeping qualities of postharvested greenhouse produce the antimiocrobial actions of Polygonum cuspidatum Sieb. et Zucc. extract , which showed remarkable antimicrobial effects against microorganism causing the postharvest decay of greenhouse produce, were investigate. In the inhibitory experiment of enzymes related to energy production metabolism hexokinase activities decreased to 73% and 68% by treating with Polygonum cuspidatum Sieb. et.Zucc. extract and Eugenia caryophyllata Thumnberg extract in comparison with control, respectively. Direct visualization of microbial cells by using both transmission electron microscope and scanning electron microscope showed that microbial cell membrane was destroyed by treating with the dilute extract solution. this change of celluloar membrane permeability could be identified in the experiment that 0-nitrophenyl-${\beta}$-D-galactopyrano-side(ONPG), the artificial substrate of ${\beta}$-galactosidase, was hydrolyzed in the presence of the extract, indicating that the membrane was perturbed. The separation and identification of the most antimicrobialo substances isolated from Polygonum cuspidatum Sieb et. Zucc. extract and Eugenia caryophyllata Thunberg extract were carried out by using gas chromatography and mass spectrometry 9GC/MSD), which were identified as eugenol. As a result, the functionality of Polygonum cuspidatum Sieb. et Zucc. extract and Eugenia caryophyllata Thunberg extract as antimicrobial agents for keeping qualities of postharvested greenhouse produce may be recommended.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.312-318
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• 1999

Volatile compounds in salt fermented anchovy on the market were analyzed by vacuum simulta neous distillation solvent extraction/gas chromatography/mass spectrometry/olfactometry(V SDE/ GC/MS/O) and aroma extract dilution anlaysis(AEDA). Predominant odorants(Log3FD$\geq$8) in sample were ethyl methylbutanoate(candy like/sweet) and 2 ethyl 3,5 dimethylpyrazine(nutty/baked potato like). Besides these compounds, 6 odorants such as ethyl 3 methylbutanoate(sweet/floral/ candy like), 3 methylbutanal(dark chocolate like), (Z) 4 heptenal(rancid/fish like), (methylthio) propanal(soy sauce /baked potato like), (E,Z) 2,6 nonadienal(melon /cucumber like) and (E,E) 2,4 decadienal(fatty/cooked soybean like) were potent in odor value of salt fermented anchovy. Seven amino acids having high taste value in sample were glutamic acid, aspartic acid(sour and umami taste), lysine, alanine(sweet), histidine, valine, and methionine(bitter).

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.319-325
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• 1999

Volatile flavor compounds in Korean salt fermented shrimp on the market were analyzed by vacuum simultaneous distillation solvent extraction/gas chromatography/mass spectrometry/olfac tometry(V SDE/GC/MS/O) and aroma extract dilution anlaysis(AEDA). A total of 32 volatile com pounds were detected by GC/O analysis. Of these, 18 were positively identified, and composed of S containing compounds(5), aldehydes(4), ketones(3), N containing compounds(3), ester(1), alcohol(1) and aromatic hydrocarbon(1). Predominant odorants(Log3FD$\geq$4) in salt fermented shrimp were 2,3 butanedione(sour/buttery), 1 octen 3 one(earthy/mushroom like), dimethyl trisulfide(cooked cabbage /soy sauce like) and 2 acetylthiazole(grainy/nutty). Predominant free amino acids were aspartic acid, glutamic acid(sour and umami taste), arginine, methionine(bitter) and lysine(sweet and bitter) in evaluation of taste value.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.139-147
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• 2019

Glutamate decarboxylase catalyzes the conversion of glutamate to gamma-aminobutyric acid (GABA), contributing to pH homeostasis through proton consumption. The reaction is the first step toward the GABA shunt. To date, the enzymes involved in the glutamate metabolism of Photobacterium damselae subsp. piscicida have not been elucidated. In this study, an open reading frame of P. damselae subsp. piscicida, showing homology to the glutamate decarboxylase or putative pyridoxal-dependent aspartate 1-decarboxylase genes, was isolated and cloned into an expression vector to produce the recombinant enzyme. Preliminary gas chromatography-mass spectrometry characterization of the purified recombinant enzyme revealed that it catalyzed not only the decarboxylation of glutamate but also the transamination of GABA. This enzyme of P. damselae subsp. piscicida could be bifunctional, combining decarboxylase and transaminase activities in a single polypeptide chain.

• Analytical Science and Technology
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• v.5 no.4
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• pp.443-454
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• 1992

The analysis, hydrolysis mechanism, oxidation, reduction, thermal decomposition and metabolism of irritant materials such as chloroacetophenone isomers, bromophenylacetonitrile isomers, o-chlorobenzylidenemalononitrile(CS), and ethylisothiocyanate, etc. are interested in forensic science. We had studied hydrolysis of CS in 10% MeOH-$H_2O$ and 10% dioxane-$H_2O$ at pH 1.0~11.0 and various temperatures. As a result, we identified o-chlorobenzaldehyde and malononitrile that were formed by hydrolysis of CS by using gas chromatography/mass spectrometry, UV/Vis spectrometry, and polarographic method.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.526-534
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• 2019

Chlorella gloriosa (Chlorellaceae, Trebouxiophyceae) was isolated from seawater off the coast of the Dokdo Islands in Korea. An axenic culture was established using the streak-plate method on f/2 agar media supplemented with antibiotics, allowing identification of the isolate by morphological, molecular, and physiological analyses. The morphological characteristics observed by light and electron microscopy revealed typical morphologies of C. gloriosa species. The molecular phylogenetic inference drawn from the small-subunit 18S rRNA sequence verified that the microalgal strain belongs to C. gloriosa. Additionally, gas chromatography-mass spectrometry analysis showed that the isolate was rich in nutritionally important omega-3 and -6 polyunsaturated fatty acids and high-performance liquid chromatography analysis revealed that the high-value antioxidants lutein and violaxanthin were biosynthesized as accessory pigments by this microalga, with arabinose, galactose, and glucose as the major monosaccharides. Therefore, in this study, a Korean marine C. gloriosa species was discovered, characterized, and described, and subsequently added to the national culture collection.