• Analytical Science and Technology
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• v.35 no.6
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• pp.229-236
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• 2022

Lipidomic analyses of transient breast milk are far more limited than those of other dairy products. As a preliminary analysis of breast milk lipidomes, analytical methods for polar and nonpolar lipids from transient breast milk were developed, and detailed fatty acid profiles were determined in this study. The newly developed methods include solvent fractionation of phospholipids and acyl glycerol, one-pot derivatization to FAMEs and pyridylcarbinol esters, and instrumental analysis, including GC-FID and GC-MS. The results indicate that breast milk contains 16 major common fatty acids with 8-22 carbons. Additionally, 29 minor fatty acids were identified, including odd-numbered fatty acids and branched analogues with 11-23 carbons. Their detailed concentrations in different fractions were measured using the internal standard method. In addition to ordinary fatty acids, breast milk contains several branched fatty acids, including iso/anteiso acids with 15-18 carbons. Structural studies have been performed on selected minor fatty acids via chemical synthesis.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.8-13
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• 2024

Objectives: To evaluate the levels of exposure to organic compounds during aircraft disinfection and seat cover replacement operations. Methods: According to the working schedule, organic compounds were collected using activated carbon tubes and then analyzed by GC/FID and GC/MSD. Results: In the disinfection task, the main substances listed in the material safety data sheet (MSDS) of the disinfectant were not detected. However, 1-bromopropane, which had been used in the previous task of replacing seat covers, was detected at a level of 2.37 ppm at the measurement time. During seat cover replacement, bonding workers were exposed to 2.48 ppm on an eight-hour time-weighted average, and seat cover replacement workers were exposed to 0.22 ppm. Conclusions: It is necessary to ensure the reliability of MSDS. A work environment management system is necessary when different companies alternate working in the same place.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.253-259
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• 2012

Wastewater-adapted microalgae such as Chlorella vulgaris AG10032, Ankistrodesmus gracilis SAG278-2 and Scenedesmus quadricauda AG10308 are useful biological resources for recovering biofuel and other bio-based materials from wastewater because of their efficient removals of nitrogen and phosphorus from wastewater and their high fatty acid contents in biomass. Although the concentrations of phosphorus typically vary in wastewater environment, very little is known about the effect of phosphorus concentration, especially phosphorus starvation, on microalgal fatty acid synthesis. This is partially due to the lack of methodological establishment for algal fatty acid analysis. In this study, we compared the analysis performances of microalgal fatty acids by two different methods; one is a non-polar GC (gas chromatography) column based method, which is generally used for microbial fatty acids, and the other is a polar WAX-type GC column method, which is typically used for plant fatty acids. And then, we explored the effect of phosphorus concentration levels on fatty acid production in microalgae cultivated from wastewater. As results, the polar WAX-type column method has better ability to separate poly unsaturated fatty acids (PUFA) including $C_{18:3}$ (linolenic acid), and was found to be more applicable in analyzing fatty acids from wastewater-cultivated microalgae than the non-polar column method. The fatty acid characterization by the WAX-type column method revealed little effect of phosphorus starvation on the quantity and composition of fatty acids from wastewater-cultivated microalgae.

• 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 Food Hygiene and Safety
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• v.3 no.2
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• pp.65-73
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• 1988

T-2 toxin is one of mycotoxins produced by fungi such as Fusarium spp. and possesses a potent cytotoxicity to eukaryotic cell. The contamination of mycotoxins in cereals and feedstuffs is one of the great concerns in health authorities. Therefore, the development of the specific, sensitive and simplified analysis method for T -2 toxin is required. During more than ten years, several chemical and biological analysis methods were proposed and applied for the detection and quantification of T-2 toxin. TLC, GLC-FID and GC-MS are widely employed, but these methods required numerous clean-up procedures before analysis, and the detection limit for T-2 toxin is more than 10 ppb. Biological analysis methods with dermal tissues and cultured cells are not specific to T-2 toxin, since T-2 toxin and other related derivatives possess a similar toxicological activity although their relative activity is different each otber. Based on tbe specific reaction between antibody and antigen, the authors tried to introduce the immunochemical methods for determination of T-2 toxin. The enzyme-linked immunosorbent assay method using monoclonal antibody for T-2 toxin was applied to analyse T-2 toxin. The detection limit of T-2 toxin by ELISA method was 0.1 ppb. The correlation between ELISA and GC-MS method on these samples was very high. ELISA method developed for the detection and quantification of T -2 toxin in this paper possesses simplicity, high sensitivity and specific for T-2 toxin. Furthermore, the ELISA method with T-2 toxin monoclonal antibody was an excellent tool for the screening of Fusarium spp. which was suspected to produce T-2 toxin.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1006-1011
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• 1998

Volatile flavor components in three varieties (shingo(niitaka), mansamgil (okusankichi) and chuwhang pears) of Pear (Pyrus pyrifolia N.) were extracted for 24 hours with pentane-diethylether (1 : 1, v/v) using the LLEP (liquid-liquid extraction & perforation). Neutral fraction was separated from the extract and then analyzed by GC-FID and GC/MS equipped with a fused silica capillary column (Carbowax 20M, HP). Individual components were identified by mass spectrometry and their retention indices. The totals of 52, 47 and 22 volatiles were identified in shingo, mansamgil and chuwhang pears, respectively. Ethyl acetate, propyl acetate, hexanal, 1-hexanol, ethyl butanoate, ethyl-3-hydroxy butanoate, ethyl-2-hydroxy propanoate were the main components in each samples, though there were several differeces in composition of volatile compounds. Total contents of volatile components isolated in shingo, mansamgil and chuwhang pears were 6.972, 2.776 and 2.653 mg/kg of pears.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.301-307
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• 1999

When fats are irradiated, hydrocarbons contained one or two fewer carbon atoms are formed from the parent fatty acids. A method to detect radiation-induced hydrocarbons consists of the extraction of fat from beef, pork and chicken, separation of hydrocarbons with a florisil column and identification of GC/MS methods. When beef, pork and chicken were irradiated, pentadecane, 1-tetradecene, heptadecane, 1-hexadecene, 8-heptadecene, 1,7-hexadecadiene, 6,9-heptadecadiene and 1,7,10-hexadecatriene were formed from palmitic, stearic, oleic and linoleic acids. Concentrations of the produced hydrocarbons tended to increase linearly with the dose levels of irradiation. Concentrations of hydrocarbons produced by ${\gamma}-irradiation$ depended upon the composition of fatty acids in beef, pork and chicken. The major hydrocarbons in irradiated beef, pork and chicken were 1,7-hexadecadiene and 8-heptadecene originating from oleic acid. 1,7-Hexadecadiene was the highest amount in irradiated beef, pork and chicken.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1495-1502
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• 1999

Gamma-irradiated beef and chicken at the dose levels of 0.5 to 10 kGy were subjected to the detection of radiation-induced 2-alkylcyclobutanones whether irradiated or not. Radiation-induced 2-alkylcyclobutanones were extracted from beef and chicken fats, separated by florisil column chromatography and identified with GC/MS method by selected ion monitoring(SIM). When beef and chicken were irradiated, 2-dodecylcyclobutanone, 2-tetradecylcyclobutanone and 2-(5'-tetradecenyl)cyclobutanone were formed from palmitic, stearic and oleic acids. Concentrations of 2-alkylcyclobutanones were linearly increased with the dose levels of irradiation and depended upon the composition of fatty acids in beef and chicken. Radiation-induced 2-alkylcyclobutanones in irradiated beef and chicken were remarkably detected at 1 kGy and over, while these compounds were not detected in non-irradiated samples. The concentrations of radiationinduced 2-alkylcyclobutanones were relatively constant during 6 months.

• 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 Food Hygiene and Safety
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• v.25 no.1
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• pp.36-42
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• 2010

The method for the determination of ethylenediamine (EDA) and hexamethylenediamine (HMDA) in food simulants was developed, and migration amounts of these compounds was monitored for 124 polyamide (PA) utensils. The diurethane derivatives of EDA and HMDA, which produced by reaction with ethyl chloroformate, were analyzed by using gas chromatograph (GC)/flame ionization detector (FID) and GC/mass spectrometer (MS). The developed method was validated with $0.3\;{\mu}g/mL$ of limit of detection (LOD) for EDA and $0.1\;{\mu}g/mL$ of LOD for HMDA, > 0.999 of linearity($r^2$) and > 88% of recovery. The EDA was detected 1.31 and $02.06\;{\mu}g/mL$ for 2 samples in water. The HMDA was detected $0.29\;-\;0.93\;{\mu}g/mL$ for 3 samples in 20% ethanol and $0.26\;-\;0.44\;{\mu}g/mL$ for 10 samples in n-heptane. These migration levels were below the specific migration limits (SML) of $12\;{\mu}g/mL$ and $2.4\;{\mu}g/mL$ for EDA and HMDA established in EU.