• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1092-1098
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• 2012

Aroma compounds in sun-dried salt according to saltern material and packaging box were extracted by the headspace and were isolated by using GC-MS. These compounds were identified including ketones, heterocyclic compounds and six other compounds. Major aroma compounds in salts were identified as 4-methyl-2-pentanone, 5-methyl-3-hexanone, 4-methyl-3-penten-2-one, 2-hexanol, benzothiazole, 2,4-bis(1,1-dimethylethyl)-phenol, and 1,3,5-tri-tert-butyl benzene. However, we found no significant differences according to the saltern materials in three salts. Salts stored in Chamaceyparis obtusa (Sieb. et Zucc.) had more diverse aroma profiling than those in Pinus densiflora and Paulownia coreana. We consider that it need to research the development of high value added products for new aromatic salt.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.617-624
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• 2017

Chocolate, one of the most popular confectioneries in the world, is known for its aromatic flavor and high antioxidant activities. In this study, we investigated the effects of fermentation with commercially available lactic acid bacteria, ABT-5, on the flavor and antioxidant activities of dark chocolate. During 24 h fermentation, pH decreased from 5.52 to 3.97 and total acidity increased from 0.51 to 1.85%, whereas total polyphenol and flavonoid contents as well as DPPH and ABTS radical scavenging activities remained unchanged. Furthermore, compared with control HepG2 cells treated with unfermented dark chocolate, those treated with the fermented dark chocolate showed significantly lower levels of reactive oxygen species and higher viability under $H_2O_2-induced$ oxidative stress. Finally, GC-MS and headspace GC-MS analysis detected 4-hydroxy-2,5-dimethyl-3(2H)-furanone and 2-furanmethanol, known to enhance flavor, in the fermented dark chocolate. Collectively, these results suggest that ABT-5-fermented dark chocolate could be utilized for developing value-added dark chocolate products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.255-261
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• 2013

This study investigated changes in the physicochemical characteristics and coffee flavors of coffee beans under different roasting conditions. Four different kinds of roasted coffees were analyzed using a headspace gas chromatographic technique. The moisture content and total acidity of roasted coffee decreased whereas the pH and weight loss (%) increased, as coffee beans were roasted at higher temperatures. The Hunter's color values of the roasted coffee (indicating L (lightness) and b (yellowness)) decreased as the roasting temperature of the coffee beans increased, but a (redness) value only increased with light roasting. We also noted that the color of the Arabica coffee was darker than that of the Robusta coffee. The aroma compounds, acetaldehyde, acetone, 2-methylfuran, 2-methylbutanol, 2-methylpyrazine, furfural, 2-propanone, furfuryl alcohol, 2,5-dimethylpyrazine and furfuryl acetate were mainly analyzed. A sensory evaluation of all light-roasted coffees had flavor and sourness and those of all medium-roasted coffees had heaviness and finishness.

• Food Engineering Progress
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• v.14 no.3
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• pp.249-255
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• 2010

Ten commercial activated carbons (ACs) prepared from four different sources (bamboo, wood, peat, and coal) were evaluated for their adsorptive efficiency of six volatile compounds (isoamyl alcohol, hexanal, furfural, ethyl lactate, ethyl octanoate, 2-phenyl ethanol) which were dissolved in a 30% alcoholic model solution. These six volatile compounds are frequently found in alcoholic beverages and possibly contribute to physiological hangover due to their high concentrations. They are also generally regarded as off-flavor compounds at certain levels in alcoholic beverages such as whisky and vodka. Two hundred mL of 30% alcoholic solutions containing these six volatile compounds were treated with 0.2 g of ACs while stirring for 16 hr; the treated solutions were then measured for their adsorptive efficiencies (or removal efficiencies) by gas chromatographic analysis using two different sampling methods (direct liquid injection and headspace-solid phase microextraction). The adsorptive efficiencies of the ACs varied depending on the identity of the volatile compounds and the source material used for making the ACs. Ethyl octanoate, 2-phenyl ethanol, and hexanal were removed at high efficiencies (34-100%), whereas isoamyl alcohol, ethyl lactate, and furfural were removed at low efficiencies (5-13%). AC prepared from bamboo showed a high removal efficiency for isoamyl alcohol, aldehydes (hexanal and furfural), and 2-phenyl ethanol; these major fusel oils have been implicated as congeners responsible for alcohol hangover.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.510-519
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• 2021

Volatile Organic Compounds (VOCs) in sediments, which can cause human health problems, have been monitored in Korea since 2014. Measured VOC concentrations can be affected by matrix type and the volatility of target substances. In this study, (1) VOCs volatility and the influence of matrix interference were confirmed, and (2) internal standards (IS) method was applied to improve analytical method. For these purposes, method detection limit (MDL), calibration linearity, precision and accuracy of VOCs were compared in various matrices using the IS. Some of VOCs in sediments showed different peak areas and reduced rates compared to water matrix. It was suggested that adsorption properties of sediments hindered the migration to vapor during heat pretreatment in headspace method. A calibration curve was created in clean sand. Recovery rates for the calibration curve method and IS applying method were 64.1~83.1% and 99.1~119.3%, respectively. Relative standard deviations ranged from 11.1% to 21.6% for the calibration curve method and those for IS ranged 4.7% to 13.7%. In case of real sediment, calibration curve and 1,2-Dichlorobenzene-d4 (ODCB) among IS were not suitable. The average recovery rate of Fluorobenzene (FBZ) increased by 56.4% and Relative Standard Deviation (RSD) by 4.7%. However, the recovery rate was increased in the samples with large values of igniting intensity. This study confirmed that influence of the matrix of VOCs in sediment, and addition of IS materials improved precision and accuracy. Although IS corrects volatilization and adsorption, it is recommended that more than two types of IS should be added rather than single.

• Analytical Science and Technology
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• v.20 no.5
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• pp.361-369
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• 2007

Uncomfortable odor emitted from air conditioning system is the main cause of indoor air quality deterioration. To solve evaporator odor problems, odor active compounds, have to be identified then the quality of the product can be improved its quality. Because evaporator odor in exhaust gas has low odor intensity and discontinuity, it is very difficult to collect and analyze sample. In this study through the identification of odor compounds in condensed water, the evaluation of the eraporator was tested. Odor compounds were extracted from water by headspace-solid-phase microextraction (HS-SPME) method. The single odor was separated by GC/FID/Olfactometry (GC/FID/O) and odor active compounds were identified by GC/AED and GC/MS. Compared to air sample, result of sensory evaluation and the single odor compound appeared similarly. It was identified that odor active compounds have functional group containing oxygen such as alcohols and acids. Evaluation method of odor active compounds using condensed water in evaporator appeared effective on the side of simplicity of collection, low expanse and rapid analysis.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1920-1926
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• 2010

Yoon et $al.^1$ presented an approximate mathmatical model to describe ammonia removal from an experimental batch reactor system with gaseous headspace. The development of the model was initially based on assuming instantaneous equilibrium between ammonia in the aqueous and gas phases. In the model, a "saturation factor, $\beta$" was defined as a constant and used to check whether the equilibrium assumption was appropriate. The authors used the trends established by the estimated $\beta$ values to conclude that the equilibrium assumption was not valid. The authors presented valuable experimental results obtained using a carefully designed system and the model used to analyze the results accounted for the following effects: speciation of ammonia between $NH_3$ and $NH^+_4$ as a function of pH; temperature dependence of the reactions constants; and air flow rate. In this article, an alternative model based on the exact solution of the governing mass-balance differential equations was developed and used to describe ammonia removal without relying on the use of the saturation factor. The modified model was also extended to mathematically describe the pH dependence of the ammonia removal rate, in addition to accounting for the speciation of ammonia, temperature dependence of reactions constants, and air flow rate. The modified model was used to extend the analysis of the original experimental data presented by Yoon et $al.^1$ and the results matched the theory in an excellent manner.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.170-175
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• 2000

This study was carried out to compare the quality of licorices from various cultivating areas. licorice samples used in this study were collected from North-east and Sinkiang area in China, Mongolia, Uzvekistan and Kazahstan. The chemical components of licorice samples were analyzed and the signal patterns of the electracts were detected by the electronic nose. Contents of glycyrrhizin and glicyrrhizic acid, the key components of licorice were distributed in the region of 16.7～25.2% and 5.8～10.2%, respectively and were various according to the samples of the collected areas. In glycyrrhizin contents, root of Sinkiang showed the lowest value of 16.7%, and that of North-east the highest of 25.2%. In glycyrrhizic acid contents, root of Sinkiang showed the lowest of 5.8 %, and Kazahstan showed the highest of 10.2 %. Composition ratio of glycyrrhizin to glycyrrhizic acid was not always limear. As other components is other components affecting quality, contents of ash, starch and gums were 2.4～3.7%, 0.2～3.9%, respectively. When the headspace volatiles of licorices were analyzed using Electronic Nose System and the obtained data were interpreted using statistical method of MANOVA, characteristic patterns of licorices were different from each other according to collected area and its p value showed 0.0001. These results suggest that licorices may be discriminated from the collected areas by using Electronic Nose System.

• Analytical Science and Technology
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• v.33 no.2
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• pp.76-85
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• 2020

A stainless-steel needle (Hamilton 90022, 22 gauge, 718-㎛ o.d., 413-㎛ i.d., 51-mm length, bevel tip) with an electrochemically coated polyaniline layer having a microbore tunnel was newly prepared as a device for headspace in-needle microextraction. For designing the needle, the polyaniline layer length was optimized, and to evaluate the extraction efficiency for polycyclic aromatic hydrocarbons, numerous cyclic voltammetry scans were conducted. In addition, the optimization of the analytical conditions (including the adsorption and desorption parameters) and the validation of the analytical method were conducted. The optimized adsorption and desorption conditions were 40 ℃ for 30 min and 230 ℃ for 60 s, respectively. Finally, in this study, a polyaniline layer was electrochemically deposited on the in-needle surface, and it exhibited good thermal stability. The needle with the polyaniline layer was repeatedly used more than 200 times during this study. This method has some advantages in terms of the extraction time, extraction efficiency, and analysis cost.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.104-109
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• 2019

BACKGROUND: The invasive hornet Vespa velutina nigrithorax has becomes a public concern in rural and urban South Korea. The technologies are necessary to develop a way to counter V. velutina. In an effort to develop a way to counter V. velutina, we found that a bacillus strain, named Bacillus sp. BV-1, produces volatile compounds that attract V. velutina. METHODS AND RESULTS: Field trials of V. velutina attraction were performed using plates and traps containing BV-1 cultures grown on sugar medium. When the sugar medium and sugar-grown BV-1 cultures in the plates were placed close together, V. velutina visited preferably the plates with the BV-1 cultures. Significantly more V. velutina were caught in the traps containing BV-1 cultures than in those containing only sugar medium. Headspace solid-phase microextraction coupled with GC/MS analysis of BV-1 cultures detected 2-methyl-1-propanol, 3-methyl-1-butanol, 3-methylbutanoic acid, ethyl hexanoate, 2-pheylethanol, ethyl octanoate, and ethyl decanoate as the major volatiles. CONCLUSION: BV-1 cultures were suggested as potential agents for managing V. velutina as they produce volatile compounds that attract the hornet.