• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.991-996
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• 2000

Enzyme-linked immunosorbent assay was developed for the analysis of soy protein in foods. Competitive indirect ELISA (ciELISA) was established by using specific antibodies against the heat-stable acidic subunits (AS) of glycinin. Soy proteins in each sample used in this study were solublized in the presence of urea and DTT and boiled at $100^{\circ}C$ for 1hr and then were renatured with a cystine-containing solution. After these treatments, each isolated soy protein (ISP) heated at 60, 70, 80, $90^{\circ}C$ for 10 minutes showed almost the same curve as unheated one in the ciELISA. The detection limit of ISP was 0.3 ${\mu}g/mL$. Anti-AS antibodies have very low reactivities less than 0.1% toward non-meat proteins such as skim milk and casein and did not show any reactivities toward egg white powder and ovalbumin. When laboratory-made sausages containing ISP of $0.5{\sim}3%$ were assayed by ciELISA, the mean recovery was about 83% (C.V., 19%). In addition, the average content of soy protein in commercial sausages was 1.27%.

• Analytical Science and Technology
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• v.14 no.1
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• pp.88-93
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• 2001

To measure the levels of dioxins in food selling at local markets, meat was analyzed by high resolution gas chromatography/high resolution ass spectrometry (HRGC/HRMS). The food samples were obtained from 5 large cities of Seoul, Chunchon, Daejon, Kwangju and Busan in Korea. All the samples were minced and extracted with Soxhlet extractor for 18 hours. After extraction, extracts were cleaned up by sulfuric acid impregnated silica gel, purified on a series of silica gel, alumina, carbon column chromatography and then analyzed by HRGC/HRMS. The contaminated levels were calculated as the TEQs by multiplying with the corresponding WHO-TEFs for each congeners. The overall recoveries were ranged from 80% to 153% and the limit of detection was about 0.01 ppt at S/N>3. The levels of PCDD/Fs for beef, pork and chicken were 0.018, 0.008 and <0.001 pgTEQ/g, respectively. In addition, the levels of non-ortho-co-planar PCBs for beef, pork and chicken were 0.008, 0.002 and 0.001 pgTEQ/g, respectively. Among food samples analyzed, chicken showed the lowest level of dioxin-like compounds. Regarding congener pattern, OCDD and PCB #77 were the highest contributing congeners.

• Applied Biological Chemistry
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• v.27 no.3
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• pp.187-197
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• 1984

Samples (river water, tap water, soil, sediment, fish and shellfish) collected in Downstream Area of Nakdong River were analyzed for organochlorine pesticides by G.C. equipped with electron capture detector. Residue levels of organochlorine pesticides in the river water and tap water ranged from less than detection limit (ND) to 56ppt. Total BHC concentration in the river water and tap water were found to increase in summer and decrease in winter. The variation appeared to be related to rain fall. ${\alpha}-BHC\;and\;{\beta}-BHC$ concentration in the soil were ND-3.3ppb and ND-769.7ppb, respectively. ${\alpha}-BHC\;and\;{\beta}-BHC$ concentration in the sediment were ND-2.0ppb and ND-409.9ppb, respectively. Concentration factor of total BHC in the sediment ranged from 83 to 3213. In fish, Carasssus carassius and shellfish, Anodonta woodiana(Lea) the concentration factor of ${\beta}-BHC$ and total BHC were 2,609, 435 and 3,261, 375, respectively.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.715-720
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• 2007

The levels of butyltin compounds in poly(vinyl chloride) (PVC) food packaging using gas chromatography/mass spectrometry (GC/MS) were monitored. The analytical method, involving the ethylation with sodium tetraethylborate, was found to be selective and sensitive for mono-n-butyltin (MBT), di-n-butyltin (DBT), and tri-n-butyltin (TBT), validated by a $0.005\;{\mu}g/mL$ limit of detection (LOD), an $R^2>0.999$ for linearity, and >90% of recovery, respectively. Finally, none of the commercial food wraps and gaskets showed detectable levels of butyltin compounds.

• Analytical Science and Technology
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• v.6 no.1
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• pp.9-19
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• 1993

Fatty acid salts derived from soap can be transferred into a typical derivative with p-bromophenacyl bromide using crown ether, a catalizer by the solid-liquid phase transfer reaction in nonpolar, aprotic solvents and separated by the reverse phase high performance liquid Chromatography (RP-HPLC) and determined using UV detector. The minimal limit of detection was defined at approximately 10~50ng in accordance with the chain length. The derivatization reaction in the presence of EDTA can be applied mot only to the calcium salts but also to the other various metal salts. The recoveries of fatty acid derivatizations in the absence and presence of the midium containing the yeast extract were obtained $95.4{\pm}1.2$, and $85.2{\pm}2.4%$ respectively. The analytical method would be applicable to determine the biodegradation of fatty acid salts in nature as well as in artificial condition such as shaker flask-medium method.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.323-327
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• 2006

The Formation of acrylamide was studied in Maillard model reaction systems based on asparagine-glucose. The mixture of asparagine and glucose in equal molar ratio, and then heated at 125, 150, 175 and $200^{\circ}C$ for 10, 20 and 30 minute, respectively. The reaction products were extracted with ethyl acetate and methanol, and then isolated and detected on FFAP capillary column and HP-5MS 5% phenyl methyl siloxane column by using GC/MS. Acrylamide was detected only from methanol extracts and on FFAP capillary column, at retention time 23.53 min., and the detection limit was 4.6 ng. Acrylamide content mainly increased with increasing temperature and processing time till $175^{\circ}C$, therefore, maximal acrylamide formation occurred at $175^{\circ}C$ for 10 minute ($116{\mu}g/g$), while, above $175^{\circ}C$, higher temperatures or prolonged processing times caused a decrease of acrylamide levels, finally disappeared at $200^{\circ}C$ for 30 minute. Three major compounds were identified as 1,3-dihydroxypropanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyrane-4-one and 5-hydroxymethylfurfural, and three minor compounds also as 5-methylfurfural, 2-acetylpyrrole and N,N-dimethylcyclohexamine, from ethyl acetate or methanol extracts on FFAP or HP-5MS capillary column.

• KSBB Journal
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• v.14 no.1
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• pp.82-90
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• 1999

In order to eventually fabricate an analytical system for infectious microorganisms, we synthesized major immunochemical components, utilized them for the construction of model system, and investigated an assay concept for bacterial whole cells. For the preparation of system components, a polyclonal antibody, against Salmonella thompson as model analyte, purified by immuno-affinity chromatography was used to chemically link to streptavidin or an enzyme, horseradish peroxidase(HRP). The antibody and streptavidin was modified with sulfosuccinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate and N-succinimidyl-3-[2-pyridyldithio]propionate(subsequently activated by dithiotheritol), respectively. The modified components were reacted to synthesize antibody-streptavidin conjugates which were then purified on a two-layer chromatography column of diaminobiotin gel and Sephadex G-100. For antibody-HRP conjugates, HRP molecules were activated by $NalO_4$ oxidation and then coupled to immunoglobulin. After stabilizing with ($NaCNBH_3$, the conjugates were purified by size exclusion chromatography on Biogel A5M column. To devise a model system, such produced components were combined with a dot-blotter in which a nitrocellulose membrane($12{\mu}m$ pre size) with immobilized biotin was already located. The analyte (S. thompson cells) was reacted with the both antibody conjugates in a liquid phase, and the complexes formed were captured on the membrane surfaces by applying vacuum in the bottom compartment of the blotter to invoke biotin-streptavidin reaction. Under optimal conditions, the system enabled to identify the analytical concept for bacterial whole cells, and the lower limit of detection was approximately $1{\mu}g/m{\ell}$($10^5-10^6$ cells/m$m{\ell}$). The controlling factors were the concentrations of each antibody conjugate that caused agglutination in the presence of analyte as they increased.

• Analytical Science and Technology
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• v.24 no.2
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• pp.119-126
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• 2011

Abstract: The amount of benzene, toluene, ethylbenzene, and o-xylene (BTEX) in 30 kinds of bottled waters purchased from market and 9 kinds of tap waters from home were determined using headspace solid phase microextraction (HS-SPME). The sample was stirred at 1200 RPM G for 4 min using a magnetic bar with $100\;{\mu}m$ PDMS as adsorbent for BTEX. Then it was desorbed from the fiber for 1 min at room temperature. Quantitation was achieved using standard calibration method. The limit of detection was determined as benzene 0.39 (${\pm}0.04$) ng/mL, toluene 0.08 (${\pm}0.04$) ng/mL, ethylbenzene 0.04 (${\pm}0.01$) ng/mL, and o-xylene 0.05 (${\pm}0.02$) ng/mL. Benzene and o-xylene were not detected in any samples, but toluene was detected in 11 samples, and ethylbenzene was detected just in 3 samples among 30 investigated bottled waters. The concentration range of investigated materials for toluene and o-xylene were $0.24({\pm}0.09)\sim2.95\;({\pm}0.08)\;ng/mL$, $0.08({\pm}0.06)\sim0.93({\pm}0.10)\;ng/mL$, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.137-143
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• 2020

To ensure safety of raw materials for military foods, hazard assessment and monitoring of residual pesticides was conducted on agricultural products consumed by 9 companies based in Gyeongin and Gangwon. Residual pesticides were analyzed for 142 different products, by applying the multi-species pesticide polycomponent analysis method. Of the 36 samples analyzed, residual pesticides were detected in 7 samples, representing a detection rate of 19.4%. One particular pesticide residue was detected in peanuts, green onions, and red pepper powder, and 20 types of pesticide residues were detected in red pepper powder used in combat foods. However, all residues were found to be below the permissible level. Moreover, the hazard assessment results for Cypermethrin, Tebuconazole and EPN showed the highest concentration among the residual pesticides detected. Since the estimated intake was less than 100% as compared to the ingestion limit, it was considered to be safe. I have suggested the edit as per my understanding. Please review for accuracy, and revise appropriately if required. This is the first pesticide Risk Assessment study encompassing military requirements. Considering the results, we expect further application research, including research on reducing hazardous materials.

• Journal of the Korean Geographical Society
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• v.50 no.6
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• pp.607-619
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• 2015

It is important to detect trails accurately for finding a proper management. We examined the applicability of KOMPSAT imagery to detect trails and found that it could be an efficient alternative to track trails correctly. We selected K2 and K3 imagery with different spatial resolution. Then, we processed each imagery to get NDVI, SAVI, and SC data. And then, we identified trails by object-based analysis and network analysis. Finally, we evaluated the potential trails with F-measurement and Jaccard coefficient which are based on correctness and completeness. The results show that the applicability is quite different in each case. Among them, especially the SC data with K3 shows the most highest value; correctness of detecting legal trails is 0.44 and completeness of that is 0.54. F-measurement and Jaccard coefficient are 0.49 and 0.32. In general, although there is a limit in detecting trails by using only KOMPSAT imagery, the usefulness of KOMPSAT imagery can be a higher considering its cost efficiency and availability of acquiring periodic data.