• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.61-67
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• 2010

In this study, Solid-phase microextraction (SPME) with GC/FID was studied as a possible alternative to liquid-liquid extraction for the analysis of chlorinated solvents (PCE and TCE) and these by-products (cis-DCE, VC, and Ethylene). Experimental parameters affecting the SPME process (such as kind of fibers, adsorption time, desorption time, volume ratio of sample to headspace, salt addition, and magnetic stirring) were optimized. Experimental parameters such as CAR/PDMS, adsorption time of 20 min, desorption time of 5 min at $250^{\circ}C$, headspace volume of 50mL, sodium chloride (NaCl) concentration of 25% combined with magnetic stirring were selected in optimal experimental conditions for analysis of chlorinated solvents and these by-products. The general affinity of analytes to CAR/PDMS fiber was high in the order PCE>TCE>cis-DCE>VC>Ethylene. The linearity of $R^2$ for chlorinated solvents and these by-products was from 0.912 to 0.999 when analyte concentrations range from $10{\mu}g/L$ to $500{\mu}g/L$, respectively. The relative standard deviation (% RSD) were from 2.1% to 3.6% for concentration of $500{\mu}g/L$ (n=5), respectively. Finally, the limited of detection (LOD) observed in our study for chlorinated solvents and these by-products were from $0.5{\mu}g/L$ to $10{\mu}g/L$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.236-242
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• 2005

To develop a new detection method using irradiation-induced volatile marker compounds of red pepper powder (RP), the volatile compounds of irradiated RP (0, 1, 3, 5, and 10 kGy) were analyzed by purge and trap (P&T)/solid phase microextraction (SPME)/gas chromatography/mass spectrometry (GC/MS) methods. A total of 51 and 31 compounds were detected in IRP by SPME and P&T methods, respectively. Among these, 25 compounds, which were composed of 4 hydrocarbons, 7 aldehydes, 1 ketone, 3 alcohols, 4 aromatic compounds, 2 esters and 4 miscellaneous compounds, showed irradiation dependent manner with significant positive correlation (p<0.01 or p<0.05) between irradiation dose and relative concentration. However, all compounds except 1,3-bis(1,1-dimethylethyl)benzene were not suitable as marker compounds because of their low determination coefficients ($R^2$<0.80) between irradiation dose and their concentrations, and detectablilty in nonirradiated sample. Therefore, only one compound, 1,3-bis(1,1-dimethylethyl)benzene, was tentatively identified as a volatile marker compound to detect irradiated RP.

• Food Science and Preservation
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• v.13 no.1
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• pp.108-114
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• 2006

This study was conducted to determine the volatile flavor compositions of the essential oil and the headspace of Capsella bursa-pastoris Medicus. Essential oil and headspace from the plant were extracted by simultaneous steam distillation extraction (SDE), and solid-phase microextraction(SPME) methods, respectively. Seventy-two compounds including 28 hydrocarbons, 4 aldehydes, 6 ketones, 16 alcohols, 4 esters, 8 acids, and 6 miscellaneous ones were identified in the leaf essential oil extracted by SDE method Sixty-eight compounds including 26 hydrocarbons, 2 aldehydes, 6 ketones, 17 alcohols, 4 esters, 6 acids, and 7 miscellaneous ones were identified in the root essential oil. According to the instrumental analyses the essential oil, phytol ($21.12\%$ in leaves, $20.94\%$ in roots) was the most abundant compound Alcohols, esters, and acids were main groups of the essential oil. On the other hand, thirty-eight compounds including 18 hydrocarbons, 3 aldehydes, 3 ketones, 9 alcohols, 2 esters, 3 miscellaneous ones were identified in the leaf headspace by SPME. In root headspace, thirty-three compounds including 16 hydrocarbons, 2 aldehydes, 1 ketone, 9 alcohols, 3 esten;, and 2 miscellaneous ones were identified. Hydrocarbons($44.02\%$ in leaves, $56.98\%$ in roots) were the main components of the headspace of Capsella bursa-pastoris Medicus.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.717-722
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• 2005

Formation mechanisms of light-induced volatile compounds were studied using riboflavin-photosensitized oleic acid model systems. Volatile compounds in model systems with 4000 ppm riboflavin at $35^{\circ}C$ under light or in the dark for 39 hr were isolated and identified by a combination of solid phase microextraction (SPME), gas chromatography (GC), and mass spectrometry (MS). Total volatiles in oleic acid with riboflavin under light for 13, 26, and 39 hr increased by 90, 190, and 270%, respectively, compared to those in oleic acid without riboflavin under light. Total volatiles in samples without riboflavin under light or samples with riboflavin in the dark were not significant in tested conditions (p>10.05). Riboflavin did not act as a photosensitizer when it was dispersed in oleic acid. Heptane, octane, heptanal, octanal, nonanal, and 2-nonenal were significantly increased in riboflavin-photosensitized samples compared to those in samples without riboflavin (p<0,05). Light-induced volatile compounds including heptanal and 2-nonenal from oleic acid could be explained using singlet oxygen oxidation, the formation mechanism of which were not understood using triplet oxygen oxidation. These results will help to understand volatile formation in oleic acid containing foods stored under light.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.525-531
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• 2005

Quality characteristics of ogapiju prepared by adding different raw materials such as Acanthopanax(0, 0.1, 0.25, 0.5%), Ganoderma lucidum(0, 0.05%), pine needle (0, 0.05%), and red ginseng(0, 0.05%) were evaluated by chemical analyses and sensory evaluation. Total organic acid contents of samples containing ogapi and other medicinal herbs were higher than that of control group. Major free amino acid was histidine. Contents of total amino acid and free sugar were highest in sample C (Acanthopanax 0.1, G. lucidum 0.05, pine needle 0.50, red ginseng 0.05%). In each sample 31-49 volatile components were identified by solid-phase microextraction method, and 42 components were detected by sniff-test using GC-olfactometry. Ogapiju showed higher content of ${\alpha}-copaene$ than control group ${\alpha}-Pinene$, camphene, ${\beta}-pinene$, sabinene, ${\alpha}-terpinene,\;{\gamma}-terpinene$, p-cymene, terpinolene, ${\alpha}-thujone,\;{\beta}-thujone,\;{\alpha}-terpineol$, carvone, and ${\beta}-ionone$ were not identified in control group. Volatile composition of ogapiju was characterized by higher amount of terpenoids. Green and herbaceous note was stronger in ogapiju than control group. Sensory evaluation indicated that good taste and palatability were highest in sample C.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.137-144
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• 2015

Although instant coffee is less palatable than freshly brewed coffee, it is widely consumed primarily due to its convenience. Frequently, instant coffee is consumed in the form of a coffee-mix. It contains coffee creamer or dried skim milk, and sugar in addition to soluble coffee. The aim of this study was to investigate the volatile aroma compounds (VACs) of instant black coffee mixed with coffee creamer or dried skim milk by Gas Chromatography-Headspace-Solid Phase Microextraction (GC-HS-SPME) and sensory evaluation. A total of 16 different coffee samples including instant black coffee and coffee mixes with coffee creamer or dried skim milk, were chosen for this study. The coffee samples contained several common VACs such as pyrazine, pyridine, and pyrrole. Sensory evaluation indicated that the flavor intensity of coffee mix was less pronounced than that of instant black coffee alone. Coffee creamer and skim milk had little distinctive aroma per se; however, they significantly contributed to the flavor profile of coffee mixes, suggesting that coffee creamer and skim milk acted as flavor modifiers in coffee mix.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.191-197
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• 2015

We investigated the physicochemical properties and volatile flavor compounds in Taiwan Apple Mango (TAM) and Philippines Carabao Mango (PCM). The volatile flavor compounds were extracted using solid-phase microextraction (SPME) and analyzed by GC/MS. TAM and PCM have significantly different chemical composition, except for their crude ash. The moisture and crude fat contents were higher in TAM, whereas the crude protein and carbohydrate contents were higher in PCM. The major free sugars in order of concentration were sucrose, fructose, and glucose. We identified 56 and 59 volatile flavor compounds in TAM and PCM, respectively. Terpenes and their derivatives comprised 94.42% of the volatile flavor compounds in TAM, but only 63.79% of those in PCM. The acidic compound contents were higher in PCM than in TAM. ${\delta}$-3-Carene was the dominant flavor compound in these two mango cultivars. ${\alpha}$-Copaene, ${\alpha}$-guaiene, germacrene D, ${\alpha}$-bulnesene, and ${\gamma}$-gurjunene were found only in TAM, whereas ${\beta}$-myrcene, ${\alpha}$-phellandrene, ${\beta}$-phellandrene, ${\alpha}$-terpinolene, and cis-3-hexenyl butyrate were identified in PCM. Based on the results, we suggest that these compounds might contribute to the distinguishing flavor properties in different varieties of mango.

• Korean Journal of Food Science and Technology
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• v.44 no.4
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• pp.383-389
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• 2012

Green tea leaves grown in Jeju island were harvested at different times in 2010 and 2011. Green teas harvested in 2010 experienced higher effective accumulative temperature than green teas harvested in 2011. The free and bound volatile compounds in green tea were analyzed using headspace-solid phase microextraction gas chromatography (GC) and GC-mass spectrometry. All green teas contained the 6 major volatile compounds ${\alpha}$-methylbutanal, pentanal, (E)-2-hexen-1-ol, ${\beta}$-linalool, geraniol and ${\alpha}$-farnesene. After enzyme treatment, (Z)-3-hexen-1-ol, benzaldehyde, (Z)-3-hexenyl acetate, ${\beta}$-linalool and geraniol were increased in all green teas. (Z)-3-hexen-1-ol increased significantly in green tea harvested in 2010, and benzaldehyde increased widely in green tea harvested in 2011. However, the total volatile compounds in green teas harvested in 2011 were remarkably decreased in comparison to harvested in 2010. It was confirmed that free and bound volatile compounds in green tea are affected by low winter temperatures.

• Journal of Life Science
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• v.21 no.12
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• pp.1740-1745
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• 2011

Volatile flavor compounds of 3 commercial products of black onion extract (produced in Changnyeong, Muan and Jeungpyeong) purchased in the online/offline markets were analyzed. A total of 51 compounds were detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of carbonyl compounds (15), sulfur-containing compounds (8), aromatic compounds (6), furans (6), nitrogen-containing compounds (3), alcohols (2), acids (2) and miscellaneous compounds (10). Among carbonyls, 4 compounds including 2-methylbutanal, 3-methylbutanal, nonanal and benzaldehyde were detected in all samples, while two sulfur containing compounds, dimethyl disulfide and dimethyl trisulfide, were detected in high amounts and considered to be key flavors in black onion extracts. Particularly, thiophenes and 3 sulfur containing compounds (methylpropyl disulfide, methyl-(Z)-propenyl disulfide and methyl-(E)-propenyl disulfide) were detected only in two products. With acetic acid, furfural and pyrazines that formed through Maillard reaction during black onion aging were detected in high amounts in all samples. This also contributed to characteristic flavors such as roasted, sweet, and sour, in the flavor of black onion extracts.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.430-436
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• 2016

Solid phase microextraction and gas chromatography-mass spectrometry (SPME/GC-MS), electronic nose, and electronic tongue were used to characterize the sensory profiles of cider vinegars from Korea (K1-2), China (C1-2), Japan (J1-2), and US (U1-2). SPME-GC/MS detected acetic acid as the common volatile compound in all vinegars, in addition to isovaleric acid, octanoic acid, and phenethyl acetate. Acids and acetic esters were the major components of Korean and US vinegar samples, respectively. Chinese vinegars had high ethyl acetate content, while Japanese samples were characterized by a low content of acetic acid. Principal component analysis (PCA) pattern provided a clear categorical discrimination of Chinese vinegars by E-nose and E-tongue analyses. The instrumental sensory scores and the taste attributes for flavor ($r^2=0.9431$), sourness ($r^2=0.9515$), and sweetness ($r^2=0.8325$) were highly correlated. Therefore, SPME/GC-MS, E-nose, and E-tongue analyses may be useful tools to discriminate the sensory profiles of cider vinegars of different origins.