• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.3
• /
• pp.314-319
• /
• 2009

The identification of volatile constituents in foods is important in creating flavor compounds to improve the flavor of foods. This study was conducted to identify the flavor compounds in soybean sprouts cultivated with 4 different types of soybean seeds. A total of 52 flavor compounds were identified and composed mainly of alcohols (16), aldehydes (17), ketones (10), acids (2), furans (2), and miscellaneous compounds (5). Sprouts cultivated with Dawonkong and Orialtae showed 46 flavor compounds whereas Pungsannamulkong and Nokchaekong was 49 and 50. In total flavor compounds contents, Orialtae was the highest (19.3 mg/kg RC) and followed by Pungsannamulkong (15.83 mg/kg RC), Dawonkong (13.2 mg/kg RC), and Nokchaekong (11.3 mg/kg RC) in that order. Two groups including alcohols and aldehydes were detected high amounts in which their ratio were analyzed 32% and 51% in total flavor contents, respectively. It may be responsible for flavor in soybean sprouts. In case each flavor compound content, 2-hydroxybenzaldehyde was detected the major compound and hexanol, 1-octen-3-ol, and hexanal that the main compounds in lipid oxidation of soybean products were identified the main volatile flavor compounds in soybean sprouts.

• Journal of the Korean Chemical Society
• /
• v.43 no.4
• /
• pp.438-446
• /
• 1999

The optimum analytical method of aldehydes, ozone by-products, was established by reverse phase liquid chromatography. Six aldehydes including formaldehyde, acetaldehyde, acrolein, propionaldehyde, butylaldehyde and benzaldehyde, and one ketone including acetone were selected as aldehyde test samples through preliminary experiments. Such analytical conditions as the pH of citrate buffer solution, reaction temperature, reaction time, and concentration of DNPH, the component and composition of desorption solvent were optimized. As the result, pH 3.0 of citrate buffer solution, 40$^{\circ}C$ of reaction temperature, 15 minutes of reaction time, and 0.012% of DNPH concentration were chosen as optimum conditions. Aldehydes-DNPH derivatives in water were concentrated on $C_18$ Sep-Pak cartridge and followed by elution of their derivatives fraction with THF/ACN(70/30) mixture, and showed recoveries of the range from 87 to 107%. Separation condition on Nova-Pak $C_18$ column with low pressure gradient elution from ACN/MeOH/water(30/10/60) of an initial condition to 80% ACN of a final condition was found to give a good resolution within 20 minutes of run time. 86% to 103% of recovery for aldehydes using this method was similar to that for aldehyde using EPA Method 554 which is ranged from 84% to 103%.

• Applied Chemistry for Engineering
• /
• v.34 no.5
• /
• pp.507-514
• /
• 2023

The selective catalytic reduction (SCR) of nitrogen oxides (NO_x) was investigated in a catalyst (Ag/γ-Al₂O₃) packed dielectric barrier discharge plasma reactor. The intermittent generation of plasma in the catalyst bed partially oxidized the hydrocarbon reductant for NO_x removal to several aldehydes. Compared to using the catalyst alone, higher NO_x conversion was observed with the intermittent generation of plasma due to the formation of highly reductive aldehydes. Under the same operating conditions (temperature: 250 ℃; C/N: 8), the NO_x reduction efficiencies were 47.5%, 92%, and 96% for n-heptane, propionaldehyde, and butyraldehyde, respectively, demonstrating the high NO_x reduction capability of aldehydes. To determine the optimal condition for intermittent plasma generation, the high voltage on/off cycle was adjusted from 0.5 to 3 min. The NO_x reduction performance was compared between continuous and intermittent plasma generation on the same energy density basis. The highest NO_x reduction efficiency was achieved at 2-min high voltage on/off intervals. The reason that the intermittent plasma discharge exhibited higher NO_x reduction efficiency even at the same energy density, compared to the continuous plasma generation case, is that the intermediate products, such as aldehydes generated from hydrocarbon, were more efficiently utilized for the reduction of nitrogen oxides.

• Analytical Science and Technology
• /
• v.21 no.1
• /
• pp.14-19
• /
• 2008

Among the many odor materials, aldehyde has bad influences not only on human nose, but also on human health. Aldehyde has a strong odor at infinitesimal level, such as down to ppt concentration. Also aldehydes are highly reactive and have poor stability. Therefore, manufacture of standard gases, analysis of aldehydes are very difficult compare to other air pollution analysis. Aldehyde CRM containing 4 different aldehydes at $10{\mu}mol/mol$ (ppm) is developed by using gravimetry method according to ISO 6142 guide. The standard gases were reproduced again, and examined its reproducibility of preparation by GC-FID. The developed aldehyde CRM's certified value showed a relative expanded uncertainties of 2.11 % (95 % of confidence level, k=2).

• Korean Journal of Food Science and Technology
• /
• v.19 no.4
• /
• pp.346-354
• /
• 1987

The voflatile fraction from Korean mandarin (Citrus reticula) and valencia orange essence oil were analyzed by capillary gas chromatography and the separated components were identified from their retention time and mass pectrum. The essence oil were extracted with methylene chloride after steam distillation. The major volatile constituents of mandarin and sweet orange was limonene which accounted for 68% of total volatiles in mandarin and 87% in sweet orange. The 31 components identified from mandarin include 11 hydrocarbones, 1 ester, 10 alcohols, 4 aldehydes, 5 miscellaneous. The following 37 components were identified in sweet orange; 12 hydrocarbones, 1 ester, 11 alcohols, 8 aldehydes, 5 misecellaneous. Mandarin contained more octanal, ${\alpha}-terpinene$, terpineol, styrene, dcitronellol, citronellal, citral and farnesol while orange included more sweet orange, myrcene, ${\beta}-pinene$, linallol, decanol, ${\beta}-copaene$, elemene, ${\beta}-cadinene$, valencene.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2008.10a
• /
• pp.326-327
• /
• 2008

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2019.10a
• /
• pp.154-154
• /
• 2019

• Analytical Science and Technology
• /
• v.28 no.3
• /
• pp.236-245
• /
• 2015

Recently, candles have been widely used to create a romantic atmosphere and to heat tea. In this study, a small combustion chamber for candle was designed using an 0.008 m³ bell jar. The emission factors of combustion products were then measured. The combustion chamber includes a glass dish, which prevents candle flame from affecting the composition of the gas emitted through the exhaust outlet. The outlet in the combustion chamber was designed as a cone shape, and it was lengthened to prevent flow from the outside, which could affect the homogeneous composition of the exhaust gas. The temperature at the outlet of the chamber was 34 ℃~41℃. The major combustion products of the candle, such as such aldehydes and acids, contained oxygen. The mass specific emission rates of benzene, toluene, ethylbenzene, and TVOC were 0.04 μg/g, 0.01 μg/g, 0.02 μg/g, and 3.81, respectively. The mass specific emission rates of formaldehyde, acetaldehyde and benzaldehyde were 4.48 μg/g, 1.09 μg/g, and 0.67 μg/g, respectively. Considering the different compositions of the candle samples, their mass specific emission rates were similar to those obtained by using a large chamber 0.17 m³~50 m³ in size.

• Korean Journal of Food Science and Technology
• /
• v.39 no.2
• /
• pp.109-113
• /
• 2007

Adenophora remotiflora (Mosidae) is a perennial plant in the Campanulaceae family and a wild plant that only inhabits in Korea. This research analyzed the volatile compounds in Mosidae and their antioxidant activities. The volatile compounds in fresh, shady air-dried, and freeze-dried Mosidae were isolated by steam-distillation extraction (SDE) method using diethylether as a solvent. Volatile compounds were analyzed by gas chromatography-mass spectrometry (GC/MS). Antioxidant activities were determined using the linoleic acid system and 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Sixty and seventy-two volatile compounds were identified from fresh and shady air-dried Mosidae, respectively. In fresh Mosidae, the most abundant compounds were ethyl acetate and heptyl acetate, while ethyl acetate and limonene were the most abundant in the shady air-dried sample. Inhibition of peroxide formation by fresh Mosidae was higher than that of ${\alpha}-tocopherol$, and inhibition by shady air-dried Mosidae was same as that of ${\alpha}-tocopherol$. Furthermore, volatile compounds from shady air-dried Mosidae had higher free radical scavenging activity than ${\alpha}-tocopherol$. The freeze-dried sample showed lower antioxidant activity in both the linoleic acid system and DPPH method.

• Korean Journal of Food Science and Technology
• /
• v.52 no.5
• /
• pp.524-528
• /
• 2020

The aim of this study was to enhance the use of wheat bran in lactic acid bacteria (LAB) fermentation. LAB fermentation of wheat bran and the flavor components and amino acids of fermentation products were analyzed using gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC). The results showed that total flavor components increased by 93% and 73% in the animal-based LAB mixture (T2) and plant-based LAB mixture (T3), respectively, after fermentation. Among these components, 2,3-butanedione (diacetyl), known for its buttery flavor, was detected at concentrations of 18.44 ng/g (T2) and 16.95 ng/g (T3). Levels of hexanal and nonanal, which causes off-flavor components in wheat bran, dramatically decreased after T2 fermentation; similarly, levels of total free amino acids decreased by 37.6% (T2) and 36.7% (T3) after fermentation. This may explain why some components were bound to volatile compounds during LAB fermentation. These results suggest that LAB-fermented wheat bran is a potential value-added food material.