• Clean Technology
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• v.11 no.3
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• pp.117-122
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• 2005

N-vinyl caprolactam (NVCL), a kind of N-vinyl amide monomer, must be dissolved in continuous phase ($scCO_2$) for dispersion polymerization in supercritical carbon dioxide. Phase behavior of $CO_2$+NVCL is very important and necessary for determining initial polymerization condition and for monomer extraction from final polymer. There is the limitation of experimental method for obtaining pure properties of the monomer because of the possibility of polymerization. And N-methyl caprolactam (NMCL) is the useful solvent for the gas treating process. In the viewpoint of molecular thermodynamics, NVCL and NMCL have same functional group i.e. ${\varepsilon}$-caprolactam. In the case of NVCL, hydrogen of amide group is substituted with vinyl group and for NMCL, hydrogen of amide group is substituted with methyl group. We suggested modified group contribution method for this ${\varepsilon}$-caprolactam derivatives. This new group contribution parameter was applied to correlate $CO_2$ + N-vinyl caprolactam or N-methyl caprolactam system.

• Journal of Dairy Science and Biotechnology
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• v.34 no.2
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• pp.91-98
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• 2016

The goal of this study was to develop hydrolyzed whey protein powder (23%-GNANA) manufactured with high content of sialic acid, a marker compound that is usually present at 7% concentration in GMP obtained from the milk protein. It is a safe food, used worldwide in infant and baby foods, etc. The test substance was prepared using (7% sialic acid containing) GMP as a raw material. Alcalase, an enzyme approved as a food additive, was used after separating sialic acid, with 100% efficiency, and 23%-GNANA (composed of 23% sialic acid and protein; product name: HELICOBACTROL-23), provided by MEDINUTROL Inc. (Korea), manufactured to have high (23%) content through ethanol soaking and enrichment. Bacterial reverse mutation (Ames) test was conducted in accordance with the GLP Guideline using the test substance specified above. To detect its mutagenicity potential in microorganisms, histidine auxotrophic strains of Salmonella typhimurium, TA98, TA100, TA1535, and TA1537, and tryptophan auxotrophic Escherichia coli strain, WP2uvrA, were used. The bacterial reverse mutation (Ames) test was performed using five concentrations of the test substances (0, 61.7, 185, 556, 1,670, $5,000{\mu}g/plate$). The evaluation did not reveal repetitive increase of colony generating values and positive criteria for reverse mutagenicity for any tested concentration in the five strains regardless of the presence of metabolic activation system, and no dose-dependency. In conclusion, the safety of 23%-GNANA test substance was verified by the bacterial reverse mutation test conducted before registration of 23%-GNANA as a food additive.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.3
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• pp.95-100
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• 2006

Synthesis of the non-swelling property micas was carried out by hydrothermal method. In order to artificially induce the diffusion of ions, a rotating system was attached to the hydrothermal apparatus and by adding 0.7 mm zircon beads, synthesis of the non-swelling property micas could be performed in a low temperature area. The hydrothermal conditions for the preparation of micas were a reaction temperature of $260^{\circ}C$, for 72 hrs, using $1K_2O,\;1Al(OH)_3,\;4Mg(OH)_2\;and\;6SiO_2$ as the starting materials and a 8M-KOH solution as the hydrothermal solvent. The micas obtained under these conditions were a plate shape with a size of $2.89{\mu}m$ and showed a whiteness of over 97 %. Also, through the FT-IR analysis, because the absorption peak of the $Mg_3OH$ vibration was observed at approximately $3700cm^{-1}$, it could be known that it was phlogopite of non-swelling property showing the chemical composition of $KMg_3AlSi_3O_{10}(OH)_2$. This result was very consistent with the EDS analysis where O (41.34 %), Mg (3.88 %), Al (11.45 %), Si (17.62 %) and K (25.71%) elements were detected.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.510-518
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• 2016

Ethyl cellulose-g-poly(ethylene glycol) (EP) was synthesized by esterification of carboxylic acid functionalized methoxy polyethylene glycol (MPEG-COOH) with ethyl cellulose (EC) in order to develop a hydrophilic substrate for thin-film composite (TFC) membrane in a forward osmosis (FO) system. A porous EP substrate, fabricated by a non-solvent induced phase separation method, was found to be more hydrophilic than the EC substrate due to the presence of polyethylene glycol (PEG) side chains in the EP. Since the EP substrate exhibits smaller water contact angles and higher porosity, the structural parameter (S) of TFC-EP is smaller than that of TFC-EC, indicating that internal concentration polarization (ICP) within porous substrates can occur less when TFC-EP is used as a membrane. For example, the water flux value of the TFC-EP is 15.7 LMH, whereas the water flux value of the TFC-EC is only 6.6 LMH. Therefore, we strongly believe that the TFC-EP could be a promising candidate with good FO performances.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.567-573
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• 2017

In this work, tungsten oxide ($WO_x$) supported on SBA-15 (mesoporous silica) were prepared and applied for oxidative desulfurization of sulfur compounds in marine diesel containing about 230 ppmw of sulfur concentration. Prepared catalysts were examined by two steps; at first step, oxidation reaction carried out with hydrogen peroxide as oxidant and then the oxidized sulfur compounds were extracted by acetonitrile as solvent. Catalysts were characterized by using X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy and $N_2$ adsorption-desorption isotherms. Tungsten oxide exists as monoclinic crystal system on SBA-15 and over about 10 wt% of the $WO_x$ loading took the form of multi-layers on SBA-15. The 13 wt% $WO_x$/SBA-15 catalyst exhibite highest activity, achieving about 76.3% sulfur removal in the reaction conditions, such as catalyst amount of 0.1 g, reaction temperature at $90^{\circ}C$, reaction time for 3 h and O/S molar ratio of 10. One time oxidation reaction is enough oxidize the sulfur compounds in marine diesel completely. The repetition experiment of extraction process indicated that sulfur removal could reach 94.4% after 5 times.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.663-669
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• 2007

The solvent extracts of Sargassum muticum, which were extracted by using several solvents with different polarities, were prepared for use as natural preservatives. The S. muticum extract with 80% ethanol was sequentially fractionated with n.hexane, dichloromethane, ethylacetate, and butanol. In order to effectively screen for natural preservatives agents, we first investigated the antioxidant activities such as DPPH radical scavenging capacity, superoxide radical scavenging capacity, and xanthine oxidase inhibitory activity of the S. muticum extracts. Through the screening system, we found that dichloromethane and ethylacetate fraction had high antioxidant activity with increments of the extract concentration. The antimicrobial activities and cell growth inhibition were investigated for each strain with the different concentrations of S. muticum extracts. Antimicrobial activities were shown in ethanol, dichloromethane, and n.hexane fractions of S. muticum. However, butanol, ethylacetate and water fractions showed weak antimicrobial activity against the tested microorganisms. Among the five fractions, dichloromethane fraction showed the highest antimicrobial activities against microorganisms tested, such as Bacillus sublitis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis and Pseudomonas aeruginosa. The polyphenolic compounds from ethanol, n.hexane, dichloromethane, ethylacetate, butanol, and water fractions were 63.96 mg/g, 8.49 mg/g, 28.11 mg/g, 172.64 mg/g, 114.56 mg/g, and 34.91 mg/g, respectively. The dichloromethane fraction could be suitable for development as a food preservative.

• Analytical Science and Technology
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• v.15 no.4
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• pp.329-334
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• 2002

Tributyl phosphate(TBP) is used in solvent extraction process for radioactive waste. This compound may be degraded to dibutyl phosphate($DBP^-$), monobutyl phosphate($MBP^{2-}$) and ${PO_4}^{3-}$ by radioactive material. Amount of $DBP^-$ and $MBP^{2-}$ in TBP must be monitored because they production of these compounds means degradation of which leads to a decrease in the extraction yield. Retention behavior for $DBP^-$, $MBP^{2-}$, $F^-$, $Cl^-$, ${NO_2}^-$, ${NO_3}^-$, ${SO_4}^{2-}$ and ${PO_4}^{3-}$ are studied with AS4A-SC(Dionex) analytical column and $Na_2CO_3$/NaOH eluent by Ion chromatography. Optimum condition for these anions is 2 mM $Na_2CO_3$/1 mM NaOH eluent. All anions by this condition is well separated within 15min. Dynamic range is $10{\mu}g/mL$ - $100{\mu}g/mL$ for DBP and $5{\mu}g/mL$ - $50{\mu}g/mL$ for $MBP^{2-}$, respectively. The Detection limit for AS4A-SC are $1{\mu}g/mL$ for $DBP^-$ and $0.5{\mu}g/mL$ for $MBP^{2-}$ in this system with a $25{\mu}L$ sample loop.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.187-193
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• 2012

Acute toxicity, water resolvability and short term reproduction test on Japanese medaka (Oriyzias latipes) for evaluating alachlor susceptibility to endocrine system were studied. Alachlor is known for suspected endocrine distruptors. As the results of tests, $LC_{50}$ (Median lethal concentration) was determined as 2.36 (1.994~2.805) mg/L, and test water replaced at 7 day intervals as its water resolvability was less than 20% in 7 days. The short term reproduction tests on Japanese medaka (Oriyzias latipes) were performed with a solvent control group, a treated group (alachlor concentrations of 0.02, 0.04, 0.11, 0.27, 0.68 ppm) and a positive control group (17 ${\beta}$ estradiol, 0.01, 0.1, 0.5 ppb). The number of spawning and embryo rates were declined in a alachlor-dose dependent manner, and the number of unfertilized eggs rates were in contrast increased depending on the concentrations. Further study should be needed to confirm whether the adverse effects may be effected by the concentrations. Additionally, alachlor was evaluated as a non-vitellogenin by the result of a test of significance of the vitellogenin content test for determination of the effect of estrogen among the endocrine disruptors.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.438-444
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• 1999

The natural full-fat rice bran is reported to contain 8.4 to 14.7 wt % Lipids, but the amount and composition of bran depend on the type of rice, quality of paddy, pretreatments to paddy such as parboiling, type of milling system employed, and the degree of polishing. These lipids are usually mixtures of several class fatty acids containing palmitic acid, linolenic acid, linoleic acid, oleic acid, stearic acid, tocopherol, squalene, etc. In this study the oil rich essential fatty acid (EFA) including squalene was extracted from the domestic brown rice bran using supercritical fluid extraction (SFE) and cosolvent induced SFE process, respectively. And the extracts were analyzed with GC-MSD. The extracted amount of rice bran oil was dependent upon the operating pressure and temperature, and the fatty acid composition of oil was varied with the reduced density (${\rho}_{\gamma}$) of supercritical carbon dioxide. About 70~80% of rice bran oil was extracted in 4hrs. The cosolvent induced SFE process shortened the total extraction time, extracted greater amount of oil than SFE process. Especially squalene which was not found in solvent extract phase was identified in SFE and cosolvent induced SFE process.