• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.694-700
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• 2018

To investigate the effect of heavy metals (Cu, Cd, Hg, Pb, Zn) on mosquito Culex pipiens, 50% lethal concentration ($LC_{50}$) concentration, total lipid content, lipid content composition, and total protein content were measured. The results showed that the Hg $LC_{50}$ was $0.45mg\;kg^{-1}$ and the Hg toxicity was higher than the other metals. The results also showed that cadmium (Cd) significantly retarded the growth of mosquito larvae among the tested heavy metals. Six types of lipid bands were isolated from mosquito samples exposed to heavy metals, and five of them were identified (phospholipid, cholesterol, fatty acid, triglyceride, and cholesterol ester). The total lipid content of all treatments decreased compared to the control. In addition, the protein content of the control group ($0.51mg\;ind.^{-1}$) was higher than that of the treated group, and the protein content of the larvae treated with Hg and Cd was very low. In conclusion, heavy metals not only lower the survival rate of mosquitoes, but also affect the protein content and lipids in the mosquito's body, thereby causing growth inhibition. These results indicate that heavy metal contamination will affect the size of mosquito population by inhibiting the survival and growth of mosquitoes, and it is expected that it can be used to measure the degree of contamination using mosquito through subsequent studies.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.414-420
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• 1998

We studied the difference effects of dietary ${\alpha}-linolenic\;acid\;({\alpha}-LA,\;18:3\;n-3)$, eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) on the lowering of triacylglycerol in the liver and serum on lipid metabolism in rats. Rats were fed semipurified diets containing 10% fat with constant polyunsaturated/monounsaturated/saturated fatty acids (1:1:1) and n-6/n-3 ratio (1:2). EPA (98%) and DHA (98%) were added in diets as the ethyl esters. The concentration of liver triacylglycerol was significantly lower in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. The concentration of liver phospholipid was significantly higher in rats fed DHA than in those fed ${\alpha}-LA$ and EPA. Both EPA and DHA reduced serum triacylglycerol concentration compared with ${\alpha}-LA$, but this effect was more pronounced in the EPA diet. The activity of phophatidate phosphohydrolase in the liver microsome was significantly lower in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. but, there was no significant difference on the activities of diacylglycerol acyltransferase among the three groups. The concentration of liver triacylglycerol were correlated with changes in the microsomal phosphatidate phosphohydrolase activity (r=0.84). Hepatic NADPH generating enzyme, glucose-6-phosphate dehydrogenase was more effective to reduce the activity in rats fed both EPA and DHA than in those fed ${\alpha}-LA$. In conclusion, EPA or DHA reduced the hepatic triacylglycerol concentration by inhibiting microsomal phosphatidate phosphohydrolase, thereby inhibiting synthesis of triacylglycerol in the liver.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.621-626
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• 2005

The esterification reaction of free fatty acid with methanol was investigated in the presence of catalyst, Amberlyst-15, producing fatty acid methyl ester, namely, biodiesel. In this paper, the effects of the reaction parameters such as reaction temperature, mole ratio of alcohol to oleic acid and mass of catalyst on the catalytic activity have been examined. The results showed that the reaction rate increased about twice as the temperature increased every $20^{\circ}C$ in the reaction temperature range from 333 K to 373 K. The equilibrium conversion rate of oleic acid increased with the feed mole ratio of alcohol to acid ranging from 6:1 to 44:1. When the feed mole ratio was higher than 44:1, all the results were similar to that of 44:1. As for the influence of the mass of catalyst, the initial reaction rate increased from 1.2 to 1.3 times as the mass of catalyst doubles in the range of the catalyst weight from 5 to 20 wt%. The experiment data obtained were well described by the second reaction rate using a pseudo-homogeneous model.

• Applied Biological Chemistry
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• v.35 no.2
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• pp.110-114
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• 1992

The lipid compositions, physical and chemical characteristics of crude oil in Korean safflow, Carthamus tinctorius L., seeds were determined and proxmate composition of it were also analyzed. The proximate composition showed moisture 7.2%, carbohydrate 34.4%, crude protein 18.2%, crude fat 34.8% and ash 5.35. Specific gravity, refractive index, smoking point, melting point and titer of the crude oil were $0.922{\sim}0.927,\;1.468{\sim}1.469,\;210^{\circ}C,\;-15{\sim}-18^{\circ}C\;and\;15{\sim}18$, respectively. Iodine value, saponification value, acid value, esterification value, unsapoifiable matter and saturated fatty acid content of the crude oil were $140{\sim}152,\;186{\sim}192,\;2.6{\sim}3.5,\;179{\sim}186,\;0.8{\sim}1.3%\;and\;6.6{\sim}7.2%$, respectively. Fatty acid compositions were quantitatively determined by G.L.C. to give $70{\sim}78%$ linoleic acid, $10{\sim}23%$ oleic acid and $5{\sim}8%$ palmitic acid as main components, stearic, linolenic and myristic acid were presented in small quantities.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.115-121
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• 1980

The oils extracted with n-hexane from 6 samples of rapeseed (5 Korean samples and 1 Canadian sample) and samples of rapeseed salad oil at the market in Korea were examined. The physical and chemical characteristics of the oils were determined, and the lipid components of the oils were determined by column, thin layer-and gas liquid chromatography. The results obtained were as follows 1. The average crude fat contents in rapeseed was 43.3 % and the content of Korean was higher than that of Canadian by about 3 %. 2. The average values of specific gravity-, refractive-index, saponification value, iodine value, acid value and nonsaponifiable content of the crude oils extracted from Korean rapeseed were 0.9133, 1.4726, 103.6, 0.51 and 1.17%, respectively. 3. The average content of polar and nonpolar in total lipids were 2.7 % and 97.3 % respectively. Triglyceride was the predominant in nonpolar fraction, averaging 92.7 % of total lipids while sterol esters and diglycerides constituted 1.5 % and 1.2 % of the total. Monoglycerides, free fatty acids and free sterols were minor components of the nonpolar fraction. The polar lipids were primarily phospholipids(1.8%), but a significant amount of glycolipid (0.7%) was also found in each oil. 4. The fatty acid compositions in the total lipids showed the Korean rapeseeds averaged 46.7 % erucic, 15 % oleic, 13.4 % linoleic, 9.3 % eicosenoic and 4.3 % palmitic acids. The Canadian rapeseed, however, contained only 0.7 % of erucic acid. 5. The fatty acid compositions in nonpolar lipid fractions was similar to the pattern in those of the total lipids. But phospholipid and glycolipid fractions were lower in erucic acid content than nonpolar lipid fractions.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.96-100
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• 2008

Pungent oils are fat sources that determine the taste, flavor, and satiety of foods. They are also energy sources and regulators of lipid metabolism in humans. The present study was performed to evaluate the effects of red pepper (Capsicum annuum L.) seed oil (RPO) and sancho (Zanthoxylum schinifolium) seed oil (SCO) as pungent oils on the lipid profiles of rats fed on hypercholesterolemic diets (0.12% cholesterol), as compared to common soybean oil (SBO). There were large differences in the n-6/n-3 fatty acid ratios of the experimental oils (SBO: 8.8, SCO: 1.2, RPO: 70.1). Serum cholesterol concentrations were higher in the RPO groups than in the other groups; whereas ratios of HDL-cholesterol/total cholesterol were lower in the RPO groups. On the other hand, liver cholesterol levels were markedly higher in the SCO groups than in the RPO groups, with the SBO groups having intermediate levels; these largely reflected cholesterol ester content differences in the rat livers. It is possible that the different serum cholesterol responses observed in the RPO and SCO groups might have been related to differences in the n-6/n-3 fatty acid ratio rather than the polyunsaturated fatty acids/saturated fatty acids ratio. Serum triacylglycerol concentrations were lower in the SCO groups as compared to the other groups. Overall, the results showed a hypocholesterolemic effect for sancho seed oil as compared to red pepper seed oil in rats fed diets containing 0.12% cholesterol.

• 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 Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.380-389
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• 2020

The conversion characteristics and fuel properties for producing biodiesel (BD) by blending beef-tallow, an animal waste resource with a high-saturated fatty acid content, and sunflower-oil, a vegetable oil with a high-unsaturated fatty acid content, were investigated. For this investigation, the effects of the control factors, such as the oil-blend ratio and methanol-to-oil molar ratio, on the fatty acid methyl ester and BD production yield were also investigated. The kinematic viscosity reduction effects of BD using heating and ultrasonic irradiation were verified, and the optimal temperature of each BD-diesel fuel blend for reducing the kinematic viscosity was derived using the correlation equation. As a result, the optimal conditions for producing blended biodiesel were verified to be TASU7 and a methanol-to-oil molar ratio of 10:1. The analysis results of the fuel properties of TASU7 satisfied the BD quality standard; hence, the viability of BD blended with waste tallow as fuel was verified. The experimental results on the kinematic viscosity reduction showed that heating is more effective in reducing the kinematic viscosity because it took less time than ultrasonic irradiation, and the equipment was cheaper and more straightforward than the ultrasonic irradiation method.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.87-97
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• 2017

This study aimed at optimizing the manufacturing conditions of a milk beverage supplemented with coffee, and monitoring its physicochemical and sensory properties during storage. Raw milk, skim milk powder, coffee extract, and emulsifiers were used to manufacture the beverage. Two sucrose fatty acid esters, F110 and F160, were identified as suitable emulsifiers. The optimum conditions for the beverage manufacture, which can satisfy two conditions at the same time, determined by response surface methodology (RSM), were 5,000 rpm primary homogenization speed and 0.207% sucrose fatty acid emulsifier addition. The particle size and zeta-potential of the beverage under the optimum condition were 190.1 nm and $-25.94{\pm}0.06mV$, respectively. In comparison study between F110 added group (GF110) and F160 added group (GF160) during storage, all samples maintained its pH around 6.6 to 6.7, and there was no significant difference (p<0.05). In addition, GF110 showed significantly higher zeta-potential than GF160 (p<0.05). The particle size of GF110 and GF160 were approximately 190.1 and 223.1 nm, respectively at initial. However, size distribution of the GF160 tended to increase during storage. Moreover, increase of the particle size in GF160 was observed in microphotographs of it during storage. The $L^*$ values gradually decreased within all groups, whereas the $a^*$ and $b^*$ values did not show significant variations (p<0.05). Compared with GF160, bitterness, floating cream, and rancid flavor were more pronounced in the GF110. Based on the result obtained from the present study, it appears that the sucrose fatty acid ester F110 is more suitable emulsifier when it comes to manufacturing this beverage than the F160, and also contributes to extending product shelf-life.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.194-199
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• 2008

In this study, the effective method to esterify the free fatty acids in jatropha oil was examined. Compared to other plant oils, the acid value of jatropha oil was remarkably high, 11.5 mgKOH/g. So direct transesterification by a base catalyst was not suitable for the oil. After the free fatty acids were esterified with methanol, jatropha oil was transesterified. The activities of four solid acid catalysts were tested and Amberlyst-15 showed the best activity for the esterification. After constructing the experiment matrix based on RSM and analyzing the statistical data, the optimal esterification conditions were determined to be 6.79% of methanol and 17.14% of Amberlyst-15. After the pretreatment, jatropha biodiesel was produced by the transesterification using KOH in a pressurized batch reactor. Jatropha biodiesel produced could meet the major specifications of Korean biodiesel standards; 97.35% of FAME, 8.17 h of oxidation stability, 0.125% of total glycerol and $0^{\circ}C$ of CFPP.