• Analytical Science and Technology
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• v.24 no.3
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• pp.200-211
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• 2011

In this study, 13 compounds including four volatile fatty acids (VFA) and nine volatile organic compounds (VOC) were analyzed by cryogenic trapping-thermal desorption technique. In order to evaluate the analytical method for VFA, calibration experiments were performed using five different sorbent materials. When the calibration results are compared between different sorbents, sampling tube filled with Carbopack X showed the highest response factor (RF) for both VFA and VOC. To validate this new analytical method for VFA using cryogenic trapping-thermal desorption technique, this method was compared with alkali absorption method recommended by the odor prevention law of the Korea Ministry of Environment (KMOE). For this purpose, unknown samples were analyzed by two different methods, i.e., cryogenic trapping-thermal desorption (TD) and alkali absorption with solid phase microextraction (SPME). When the results of two different methods were compared, ratios of concentrations determined by the two analytical methods (TD/SPME) was found as 0.46 (valeric acid) ~ 0.71 (isovaleric acid). Therefore, additional study is required to properly establish and find stable analytical conditions for VFA analysis. Furthermore, comparison between two different methods should be made with more reliable calibration approaches.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.267-273
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• 2013

We aimed to improve the flavor quality of plain yogurt, which is known to be sour and less desirable in flavor, varying concentrations of a buckwheat saccharification solution (BSS) were added to milk, followed by fermentation with commercially available mixed strains of lactic acid bacteria. Volatile compounds were analyzed using the gas chromatography-headspace-solid phase microextraction (GC-HS-SPME) method. Fermentation properties, including pH, titratable acidity, viable cells, viscosity, and color value were also measured. Eleven volatile compounds were identified with GC-MS. Of which, diacetyl, butanoic acid, and 2-heptanone proportionally increased as the levels of BSS increased. Undesirable compounds such as acetic acid and 2-butanone, decreased as BSS concentration increased. Fermentation properties were significantly altered with the addition of BSS. Our findings indicate that the flavor quality of plain yogurt can be improved by adding BSS for fermentation, with an additional health benefit from buckwheat.

• Journal of Life Science
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• v.18 no.12
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• pp.1712-1717
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• 2008

Volatile flavor compounds of onions were analyzed and compared during storage at $0.5^{\circ}C$, which harvested in 6 regions, such as Muan, Buan, Andong and 3 regions of Changnyeong (Yueo, Jangma and Seongsan). A total of 45 compounds were detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of sulfur-containing compounds (21), aldehydes (13), ketones (2) and miscellaneous compounds (9). The sulfur-containing compounds were major compounds with ranges of $66.9{\sim}86.9%$ of total volatiles in 0 day of storage as regardless of harvested regions. Three regions (Yueo, Seongsan and Muan) had high amounts of over 4,043 ng/g in 0 day of storage, whereas 2 regions (Muan and Yueo) only had amounts of over 2,400 ng/g after 60 days of storage. Five sulfur-containing compounds known as having antioxidant activity (2,4-, 2,5-dimetylthiophene, 2-vinyl-1,3-dithiane, 5-methoxy thiazole and 3,5-diethyl-1,2,4-trithiolane and isomer) were the high levels in 3 regions (Yueo, Seongsan and Muan) during 60 day of storage. These 3 regions had also the highest amounts in 5 sulfur-containing compounds known as having anticarcinogenic activity ((Z)-, (E)-methyl propenyl disulfide, (Z)-, (E)-propenyl propyl disulfide, and di-2-propenyl disulfide) and kept same trend after 60 days of storage.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.527-532
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• 2010

The properties of volatile flavor components were compared in commercial brown rice vinegars that were fermented with and without ethanol addition, for which solid phase microextraction-gas chromatography (SPME-GC), electronic nose, and sensory evaluations were performed. A total of 24 volatile compounds, mainly composed of acetic acid, ethyl acetate, benzaldehyde, iso-valeric acid, phenylethyl alcohol, 2-phenylethyl acetate, acetoin, and isobutyric acid, were identified in the brown rice vinegar fermented without ethanol, while major volatiles in the brown rice vinegar fermented with ethanol were acetic acid, ethyl acetate, 1-hexyl acetate, benzaldehyde, 2-phenylethyl acetate, and phenylethyl alcohol. The electronic nose patterns of samples indicated a significant difference in the brown rice vinegars fermented with and without ethanol. Pungent flavor and off-flavor intensity were high in the brown rice vinegar fermented without ethanol. According to the results, fermentation conditions affect the volatile properties of brown rice vinegars.

• Journal of Life Science
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• v.20 no.1
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• pp.113-118
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• 2010

The study was conducted to identify volatile flavor compounds in concentrated onion extracts ($Oniwell^{TM}$) during storage at $30^{\circ}C$ for 150 days. A total of 23 compounds was detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of 9 sulfur-containing compounds, 5 carbonyl compounds, 4 furans, 2 aromatic compounds and 3 miscellaneous compounds. The sulfur-containing compounds were major compounds with ranges of 75.8~67.3% of total volatiles. In particular, dimethyl trisulfide, with a cooked cabbage-like odor, was 50.1~42.1% of the total amount of sulfur-containing compounds. Two compounds, dimethyl disulfide (fresh garlic/green onion-like) and methylpropyl disulfide (garlic salt-like), were significantly increased with longer storage periods (p<0.05). Four furans (furfural, 2-acetylfurn, 5-methyl-2-furfural, furfurylalcohol), known as thermally generated flavors, ranged from 14.2~12.9% of total volatiles, and the amounts of 4 aldehydes (2-, 3-methylbutanal, benzaldehyde, phenylactaldehyde) derived from lipid oxidation during heat treatment were followed in that order. Accordingly, it was estimated that these 3 groups including sulfur-containing compounds, furans and aldehydes played key roles in flavors in concentrated onion extracts ($Oniwell^{TM}$) during storage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.85-93
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• 2012

We study on the distribution characteristics of antifouling agents such as Sea-nine 211, Irgarol 1051, Diuron using HS-SPME method in southwestern coast of Korea. Short half-life of Sea-nine 211 was distributed in very low concentrations and/or below detection limits in all of the sampling points, both water and sediments samples. Irgarol 1051 was detected to have the highest concentration respectively $6.98{\mu}g/L$, 28.50 ng/g-dry wt in the seawater and sediments, and regional distribution characteristics did not appeared. Strong bioaccumulation and long half-life of Diuron was distributed higher concentration than in all sampling point and was analyzed to have the highest concentration(3882.22 ng/g-dry wt) Mo7(Mokpo)'s sediment. Irgarol 1051 and Diuron distributed in the shipbuilding industry and ship marina are located just at the point to found in high concentrations. In addition, the distribution of the antifouling agent materials were lower in concentration than in inner bay to outter bay in sediments. Antifouling agent materials from these results were contaminated high potential from port and shipbuilding industry located in inner bay.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.201-208
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• 2007

Functional oils (FOs) were produced from commercial diacylglycerol oil and red yeast rice extracts from 80% ethanol for 1 hr in a shaking water bath at $35^{\circ}C$ and 175 rpm. FOs contained (A) 600, (B) 1200, (C) 1800, and (D) 2280 ppm of red yeast-rice extracts, respectively. The Hunter a value and b value were risen whereas L value was reduced along with the increase of extract concentration. Content of monacolin K and total phenolic compounds in FOs significantly increased according to the increase of extract concentration. The oxidation stability of FOs was observed by Rancimat at $98^{\circ}C$. Induction time decreased according to the increase of extract concentration. The major volatile compounds of FOs were compared using the electronic nose (EN) system and solid phase microextraction (SPME) method combined with gas chromatograph/mass spectrometry (GC/MS). EN was composed of 12 different metal oxide sensors. Sensitivities (Rgas/Rair) of sensors from EN were analyzed by principal component analysis (PCA), whose proportion was 99.66%. For qualitative or quantitative analysis of volatile compounds by SPME-GC/MS, the divinylbenzene/carboxene/polydimethyl-siloxane fiber and sampling temperature of $50^{\circ}C$ were applied.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1016-1027
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• 2015

This study collected 120 figs, classified them into six degrees of maturity according to hardness values, and analyzed contents of organic acids and free sugars. Volatile compounds in figs were investigated using the solid-phase microextraction method of gas chromatography/mass spectrometry. For measurement of texture, elasticity increased up to stage 4 and decreased again. Cohesiveness and brittleness increased with maturation. Organic acids in figs were mainly composed of citric acid, malic acid, and tartaric acid in the final stage. Fructose and glucose were the major sugar components of figs. Fructose content decreased from stage 1 to stage 4 and then increased significantly. One hundred and nineteen volatile compounds were identified in figs, and classes were 14 acids, 15 alcohols, 23 aldehydes, 10 esters, 33 hydrocarbons, 11 ketones, four aromatics, six miscellaneous, and five terpenes. The dominant volatile components in figs were hexadecanoic acid, hexane, dodecanal, DL-limonene, 2-hexanal, nonanal, and 6-methyl-5-hepten-2-one.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1871-1880
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• 2014

Headspace volatile compounds of leaf, stem, and root of Peucedanum japonicum Thunberg (PJT) harvested in March and July were isolated, separated, and identified by using a combined system of solid phase microextraction and gas chromatography/mass spectrometry. Identified numbers of volatile compounds were 72, 75, and 63 in March PJT as well as 78, 73, and 69 in July, respectively. Total compounds identified from PJT consisted of alcohols (1~7), aldehydes (7~15), esters (1~4), hydrocarbons (5~9), ketones (1~2), monoterpenes (13~16), monoterpene alcohols (1~5), monoterpene aldehydes (2~4), monoterpene esters (1~4), monoterpene ketones (1~2), sesquiterpenes (16~24), and miscellaneous compounds (2~3). Major volatile compounds of PJT were monoterpenes at all harvest times and in all parts of PJT. The amounts of ${\beta}$-pinene in leaf and stem harvested in March were highest in monoterpenes, followed by ${\alpha}$-pinene and ${\beta}$-myrcene. However, amounts of volatile compounds of monoterpenes in leaf and stem from July PJT were in the decreasing order of ${\beta}$-pinene, ${\beta}$-phellandrene, and ${\beta}$-myrcene. Of the 39 sesquiterpenes identified in PJT, (E)-caryophyllene in March leaf was the most abundant volatile compound, followed by acoradiene in March leaf, ${\beta}$-elemene, and ${\alpha}$-copaene in July stem.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.102-109
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• 2014

Crab-like flavoring base (CFB) was made from a concentrated snow crab cooker effluent (SCCE) containing five food additives (proline, glycine, arginine, methionine, fructose) using reaction flavor technology (RFT). The volatile flavor compounds in CFB were compared between raw (SCCE) and control (without food additives) samples using solid phase microextraction (SPME) and gas chromatography with mass selective detector. A total of 74 compounds were detected in all samples (30 raw samples, 34 control samples, 55 CFB samples). A total of 22 nitrogen-containing compounds, including 19 pyrazines and 3 pyridines, were formed through RFT and increased 27 times compared to the control. Dimethyl trisulfide and dimethyl disulfide were predominant sulfur-containing compounds that increased through RFT, while aromatic compounds decreased through RFT. Seven compounds, tetramethylpyrazine, 2-ethyl-3,5,6-trimethylpyrazine, 2,3,5-trimethyl-6-(3-methylbutyl)pyrazine, 2-ethyl-3,5-dimethylpyrazine, 2,5-dimethyl-3-(3-methylbutyl)pyrazine, 2-ethyl-3,6-dimethylpyrazine, and 2-decanone potentially have a role in CFB odor by Pearson's correlation analysis.