• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.529-533
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• 2012

In this study, we compare various physicochemical properties of solvent extracted coals obtained at both mild and high temperature conditions. In order to characterize the extraction behavior, experiments were performed using a sub-bituminous coal (Kideco) and a polar solvent (N-methyl-2-pyrrolidinone, NMP), where the extraction temperature and the effect of solvent recycling were evaluated. As the extraction temperature increased up to $350^{\circ}C$, an extraction yield and a calorific value of the extracted coal increased, while an ash content of the extracted coal decreased. FT-IR results revealed that the surface of the coal extracted at $350^{\circ}C$ was found to contain more amide, aromatic ester, and aliphatic ether groups than that at the lower temperatures. The result of MALDI-TOF/MS analysis confirmed that the smaller molecules with 300~500 m/z were extracted at a mild condition, while the bigger molecules in the range of 500~1500 m/z were extracted at the high temperature.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.172-178
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• 2020

In this study, the optimization of the biodiesel production process from waste oil using microwave with response surface methodology (RSM) was conducted. The microwave irradiation time and power in addition to the alcohol/oil mole ratio were chosen as process parameters. Also the fatty acid methyl ester (FAME) content (over 96.5%) and kinematic viscosity (1.9~5.5 cSt) were selected as response values. From basic experiments, the range of quantitative factors were set as following; 4~6 min, 400~600 W, and 7~9 for the microwave irradiation time and power, and alcohol/oil molar ratio, respectively. The optimum conditions for the methanolysis were 5.0~5.1 min, 481.3~525.5 W, 7.9~8.4, and 2.0 or 3.0 mg KOH/g for the microwave irradiation time and power, methanol/oil molar ratio, and each acid value, respectively. The FAME content and kinematic viscosity were predicted as 97.49~96.34% and 4.01~4.12 cSt, respectively, under the condition above. Under the optimum experimental conditions, the results showed that the FAME content and kinematic viscosity of 97.82~96.42% and 4.07~4.16 cSt, respectively were measured and the mean error rates were 0.22% and 0.98%, respectively.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.246-249
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• 2010

Diacylglycerol (DAG) was produced from lipase by the catalyzed synthesis of soybean oil (SBO) and glyceryl monooleate (GMO) with Lipozyme TLIM (Thermomyces lanuginosa). Effects of reaction time, molar ratio and enzyme road were studied. When 2:1, 1:1 and 1:2 (SBO:GMO) molar ratios with 20% Lipozyme TLIM were applied in a 1-hr reaction, the concentrations of DAG produced were 17.8, 20.0 and 20.4 g/100 g oil, respectively. Different amounts (2, 5, 10 and 20%) of Lipozyme TLIM were used at a 1:2 (SBO:GMO) molar ratio, and the concentrations of DAG produced in a 1-hr reaction were 10.8, 14.0, 16.9 and 20.4 g/100 g oil, respectively. During a 72-hr reaction, 10.8-22.7 g/100 g oil of DAG were produced under the reaction conditions in this study.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.369-376
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• 2017

Maturation of distilled spirit can generate diverse flavors and tastes. Rice Soju was matured in oak casks (MSO) and stainless steel containers (MSS) for one year at ambient temperature. Ipguk (Aspergillus luchuensis) and Saccharomyces cerevisiae Y88-4 were used, and reduced pressure ($110{\pm}20Torr$) distillation was applied to brew Soju. Acidity and conductivity were increased in both MSO and MSS. MSO reduced alcohol content (from 43 to 40%) and volume (from 18,000 to 12,730 mL), and significantly altered yellowness (from 0.2 to 30.2). Furthermore, MSO increased the isoamyl alcohol (from 276.7 to $339.2{\mu}g/mL$) and isobutyl alcohol (from 122.3 to $144.2{\mu}g/mL$) content. Gas chromatography-mass spectrometry was used to detect volatile compounds in Soju, which included 20 esters, 7 alcohols, 2 acids, and 5 miscellaneous compounds. Oak lactone was detected only in MSO and was considered as a specific flavor component associated with oak maturation. Thus, maturation materials contribute to the physicochemical property of distilled spirits.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.524-528
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• 2002

The study was carried out to evaluate the antioxidant activity of grape seed extracts by measuring acid value, peroxide value (POV), thiobarbituric acid reactive substances (TBARS value) and electron donating ability by 1,1-dipheny1-2-pycryl hydrazil (DPPH) method. Total phenol content of freeze dried crude solvent extracts increased in the order of ethanol>acetone>hot water. Among extracts, the total phenol content of 70% ethanol extract of grape seed (GSE) was the highest, 51%. Besides the total phenol, the other major components of GSE were crude carbohydrate (29.63%), crude protein (3.38%) and crude lipid (2.84%). The acid values of crude rice bran oil containing GSE or several antioxidants at the concetration of 0.01% were 52.3 for the control, 0.5 for GSE, 2.3 for dibutyl hydroxytoluene (BHT), 45.0 for tertiarybutyl hydroxy quinone (TBHQ), 29.9 for tocopherol and 37.7 for ascorbic acid. The POVs for linoleic acid methyl ester in the presence of 0.01% antioxidants were 1220 meq/kg in control, 55 meq/kg in GSE, 104 meq/kg in BHT, 952 meq/kg in tocopherol and 71 meq/kg in GSE, 37% in BHT, 37% in tocopherol and 52% in ascorbic acid. The electron donating abilities by DPPH in the presence of 0.01% antioxidants were 95.3% in GSE, 75.0% in BHT, 96.3% in tocopherol and 98.2% in ascorbic acid. These results indicated that the antioxidants activities of GSE were significantly higher than those of several antioxidants compared.

• Korean Journal of Food Science and Technology
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• v.10 no.3
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• pp.313-319
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• 1978

In order to investigate the effect of dietary long chain fatty acids on fatty acid biosynthesis of liver in birds, single comb White Leghron male chicks were fed a fat-free diet an diets containing margaric, stearic and linoleic acids and liver lipid components and liver and plasma fatty acid distributions were compared. Total lipids of tissues were extracted with a chloroform-methanol mixture. The lipid components were determined by thin layer chromatography and fatty acid distribution of lipid fractions were determined by gas liquid chromatography. Fatty acid feeding did not affect liver lipid components. When margaric acid(17 : 0), was fed, 17:0 and heptadecenoic acid(17:1) appeared in every lipid fractions of liver and plasma, and distribution values of these acids were not significantly different between the lipid fractions of liver. In blood plasma of the 17 : 0 fed chicks, however, significantly higher distribution values of 17 : 0 and 17.1 were observed in the triglyceride fraction and in the cholesterol ester fraction, respectively. Dietary stearic acid (18 : 0) did not show any effect on the distribution of 18 : 0 in every lipid fractions of liver but showed a significantly higher distribution value of 18 : 0 in the free fatty acid fraction of plasma. When linoleic acid (18 : 2) was fed, every lipid fractions of liver and plasma contained 18 : 2, especially a significantly higher distribution value was observed in the phospholipid fraction of liver. Dietary margaric and linoleic acids tended to decrease the distribution value of endogenously synthesized palmitoleic (16 : 1) and oleic (18 : 1) acids in liver.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.717-726
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• 2017

The current allowable cross-contamination level of fatty acid methyl esters (FAME) in aviation turbine fuel (AVTUR) is 50 mg/kg, due to that the presence of FAME in AVTUR can significantly impact the fuel supply system and jet engine. It has been difficult to analyze the level of FAME in AVTUR, since it is consisted of a lot of hydrocarbons. In this study, thus, a new method using multi-dimensional GC-MS (MDGC-MS) was proposed in order to determine the FAME level in AVTUR effectively. Applying to MDGC-MS with Deans switching system enabled us to detect and quantify the FAME with low carbon numbers such as those derived from coconut oil and palm kernel oil. The matrix effect of MDGC-MS method, which could shift the FAME peaks to slightly longer retention times, was reduced by 20 times compared with that of 1-dimensional GC-MS reference method. This developed method could be suitable for qualitative and quantitative analyses to determine the contamination level of trace FAME in AVTUR.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.241-249
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• 1993

The class and fatty acid composition of neutral lipid(NL) and phospholipid(PL) of Korean sweetfish were experimented. The NL was mainly consisted of triglyceride ($94.8{\sim}99.5\%$), and also identified free sterol($0.29{\sim}2.77\%$), sterol ester and diglyceride in less quantity. Triglyceride content of viscera was much higher than those of other tissues. Main components in the PL were phosphatidylcholine(PC, $7.9{\sim}61.6\%$), phosphatidyl ethanolamine(PE, $19.3\%{\sim}39.3\%$) and followed by diphosphatidyl glycerol and sphingomyelin. PC and PE contents were higher in muscle and head tissues. The major fatty acids in NL fractions of sweetfish were 16:0, 18:1n-9, 16:1n-7, 18:2n-6, 18:0 and 14:0. Fatty acid composition of NL was similar to those of total lipid and were not significantly different among the fishes, the large and small sweetfish. In case of PL fractions, the major fatty acids were 16:0, 18:1n-9, 22:6n-3, 18:0 and 18:2n-6.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.689-696
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• 1997

The effects of Aralia canescens and Phellodendron amurense(AP) extracts on the experimental diabetes in ICR mice were investigated. 96male ICR mice were induced diabetes mellitus by intrape-ritoneal streptozotocin injection(75mg/kg B.W.) and divided into two injection groups which are 5 day injection and 10 day injection group. Then, each injection group was subdivided into 8 groups of 6 animals repspectively. CIC served as control and CI1, CI2 and CI3 were treated with 50, 150, 250mg/kg B.W. of AP extracts powder in 0.9% NaCl solution. Animals of groups DIC, DI1, DI2 and DI3 were strepto-zotocin-induced diabetes. DIC served as diabetic control and the rest groups received 50, 150, 250mg/kg B.W of AP extracts powder in saline solution respectively. The body weight, liver and kiney weight changes and blood levels of glucose, cholesterol and triglyceride were measured. Thiobarbituric acid reactive substance(TBARS), and glutathione reductase(GR) and glutathione peroxidase(GPx) activities were also measured for determining antioxidant effects. AP extracts increased the body weight in diabetic groups. The liver and kidney weight/100g B.W. in DIC group were greater than those of normal ICR group but after AP extracts injection, liver and kidney weight were decreased significantly. These effects were more efficient at 10 days injection group. The total, LDL, VLDL cholesterol and triglyceride levels were significantly higher in DIC group and the extent of decrement responded to AP injection dose. The contents of TBARS and antioxidant enzyme activities were relatively decreased after AP extracts injection. These results suggest that the intraperitoneally administered AP extracts may have not only hypoglycemic effect but act as antioxidants by reducing lipid peroxidation.

• Elastomers and Composites
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• v.39 no.3
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• pp.217-227
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• 2004

A new thermotropic liquid crystalline polymer(TLCP) containing a triad aromatic ester type mesogenic unit and butylene terephthalate unit(BT) in the main chain was synthesized by polycondensation reaction. The TLCP synthesized showed nematic mesophasic behavior and its transition temperature from solid to mesophase was $260^{\circ}C$. The TLCP/PBT blends were prepared by in-situ polymerization in PBT solution and characterized by differential scanning calorimeter(DSC), thermogavimetric analyzer(TGA), scanning electron microscope(SEM), x-ray diffractometer(XRD), and dynamic mechanical thermal analyze, (DMTA). The blends showed well dispersed TLCP phases with domain sizes $0.05{\sim}0.2{\mu}m$ in the PBT matrix. As the increasing TLCP content from 5 to 20 wt%, ${\Delta}Hm$ values of pure PBT in the blend were increased because TLCP acts as a nucleating agent in the PBT matrix. The mechanical properties of the blends depended on the TLCP contents because the TLCP acted effectively as a reinforcing material in the PBT matrix. The blends showed good interfacial adhesion between the TLCP phase and PBT matrix.The blends prepared by in-situ polymerization showed higher mechanical properties and well dispersed TLCP domains than those of the blends prepared by melt blending.