• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1625-1632
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• 2005

This study was conducted to monitor the extraction yields and functional properties from cabbage by a response surface methodology. The extract yield was maximized as 44.47$\%$ under the temperature of 79.86$^{\circ}C$, ethanol concentration of 56.84$\%$ and solvent to sample ratio 25.58 mL/g . The maximum value of electron donating ability was 85.46$\%$ at 46.38$^{\circ}C$,57.06$\%$ of ethanol concentration and 27.71 mL/g of solvent to sample ratio. The maximum value of tyrosinase inhibitory effect was 69.37$\%$ at 37.5$^{\circ}C$,47.71$\%$ of ethanol concentration and 16.03 mL/g of solvent to sample ratio. The maximum value of SOD-like activity was 48.36$\%$ in 66.12$^{\circ}C$, 70.35$\%$ of ethanol concentration and 29.13 mL/g of solvent to sample ratio. Estimated conditions for the maximized extraction including yield, electron donating ability and SOD-like activity were 20 $\∼$ 30 mL/g in ratio of solvent to sample, 25$\∼$85$\%$ in ethanol concentration, and 40$\∼$90$^{\circ}C$ in extraction temperature.

• 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.

• Resources Recycling
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• v.32 no.1
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• pp.21-32
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• 2023

Because the application of lithium has gradually increased for the production of lithium ion batteries (LIBs), more research studies about recycling using solvent extraction (SX) should focus on Li⁺ recovery from the waste solution obtained after the removal of the valuable metals nickel, cobalt and manganese (NCM). The raffinate obtained after the removal of NCM metal contains lithium ions and other impurities such as Na ions. In this study, we optimized a selective SX system using di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant and tri-n-butyl phosphate (TBP) as a modifier in kerosene for the recovery of lithium from a waste solution containing lithium and a high concentration of sodium (Li⁺ = 0.5 ~ 1 wt%, Na⁺ = 3 ~6.5 wt%). The extraction of lithium was tested in different solvent compositions and the most effective extraction occurred in the solution composed of 20% D2EHPA + 20% TBP + and 60% kerosene. In this SX system with added NaOH for saponification, more than 95% lithium was selectively extracted in four extraction steps using an organic to aqueous ratio of 5:1 and an equilibrium pH of 4 ~ 4.5. Additionally, most of the Na⁺ (92% by weight) remained in the raffinate. The extracted lithium is stripped using 8 wt% HCl to yield pure lithium chloride with negligible Na content. The lithium chloride is subsequently treated with high purity ammonium bicarbonate to afford lithium carbonate powder. Finally the lithium carbonate is washed with an adequate amount of water to remove trace amounts of sodium resulting in highly pure lithium carbonate powder (purity > 99.2%).

• Biomedical Science Letters
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• v.12 no.3
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• pp.177-183
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• 2006

To demonstrate the effect of formulation conditions and evaluations of structural integrity from ovalbumin containing poly lactide glycolide copolymer (PLGA) microspheres for Vaccine delivery, OVA microspheres were prepared by a W/O/W multiple emulsion solvent extraction technique. Dichloromethan (DCM) and Ethyl acetate (EA) were applied as an organic phase and poly vinyl alcohol (PVA) as a secondary emulsion stabilizer. Microspheres were characterized for particle size, morphology (optical microscopy and Scanning Electron Microscope (SEM)). Protein denaturation was evaluated by size exclusion chromatography (SEC), SDS-PAGE and isoelectric focusing (IEF). Residual organic solvent was estimated by gas chromatography (GC) and differential scanning calorimetry (DSC). Optical photomicrograph and SEM revealed that micro spheres were typically spherical but various morphologies were observed. Mean particle size $(d_{vs})$ of microspheres were in the range of $3{\sim}50{\mu}m$. Also, The protein stability was not affected by the fonnulation process and residual organic solvent was beyond the detection below 0.1ppm. These results demonstrated that micro spheres might be a good candidate for the parenteral vaccine delivery system.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.855-859
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• 2000

An application of synergistic solvent extraction for the etermination of trace lithium in sea water has been studied by forming an adduct complex of thenoyltrifluoroacetone (TTA) and trioctylphosphine oxide (TOPO) in a solvent. The interference by major constituents in sea water was eliminated by phosphate precipitation. Ex-perimental conditions such as solution pH, concentrations of TTA and TOPO etc. were optimized in synthetic sea water with similar compositionto its natural counterpart. To eliminate the interference, 1.38g of ammoni-um dihydrogen phosphate and 2.5 mL of ammonia water were added into 100 mL of thediluted solution at $60^{\circ}C$ to form the phosphate precipitates of Ca2+ and Mg2+ ions. After the pH of this filtrate was adjusted to 8.0, 10.0 mL of m-xylene containing 0.1 M TTA and 0.05 M TOPO was added to the solution in a separatory funnel, and the solution was shaken vigorously for 20 minutes. The solvent was separated from the aqueous solution, and 20 uL of m-xylene solution was injected into a gaphite tube to measure the absorbance by GF-AAS. The detection limit was 0.42 ng/mL. Lithium was determined within the range of 146 to 221 ng/mLin Korean coast-al sea waters, and the recoveries in the spiked samples were 94 to 106%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.189-197
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• 1977

In present study, the effects of various factors including the solvent concentration, extraction time and temperature, the ratio of sample vs extraction solvent, (w/v) and pH upon the extractability of the NaCl and alcohol soluble proteins of marine algae were investigated. Eight species of fresh algae, the major ones in consumption as food, namely Porphyra suborbiculata, Undarie pinnatifida, Hizikia fusiforme, Sargassum, fulvellum, Enteromorpha linza, Sargassum kjellmanianum, Codium coarctatum, and Ulva pertusa were used for the extraction of NaCl soluble protein and dried materials of four species, Perphyra suborbiculata, Undaria pinnatifida, Enteromorpha linza and Sargassum fulvellum were used for the extraction of alcohol soluble protein. The frozen and mascerated samples were prepared by the same method described in previous paper (Ryu, 1977). And the dried materials were moistened with alcohol solution before freezing. The effect of solvent concentration on the extractability of NaCl soluble protein differed from species. The extractability of Undaria Pinnatifide, Hizikia fusiforme, Perphyra suborbiculata, Enteromorpha linza, and Ulva pertusa reached maxima at 0.25M NaCl solution while the 1.0M for Sargassum fulvellum, Saygassum kjellmanianum and Codium coarctatum. In case of alcohol soluble proteins, it was shown at $20\%$ ethanol solution for Porphyra suborbiculata, Undaria pinnatifida, Enteromorpha linza, and Sargassum fulvellum. Variation of the ratio of sample vs solvent gave slight effect upon the extractability, but the ratio of 1:30(w/v) seemed most efficient for the extraction of NaCl soluble proteins and 100 ml solvent added to 1 g dried sample was effective in case of alcohol soluble proteins. Extraction time has a minimal effect upon the extraction of alcohol soluble protein, and approximately 21 to $43\%$ of algal protein was extracted within 1 hour. But in case of NaCl soluble protein extraction, the effect of time revealed differently from species to species resulting in that the extraction for 1 hour gave a maximum extractability in Ulva pertusa and Enteromorpha linza, 2 hours in Porphyra suborbiculata, Codium coarctatum and 3 hours in Undaria pinnatifica, Hizikia susiforme, Sargassum fulvellum and Sargassum kjellmanianum. When the NaCl soluble protein of Undaria pinnatifida and Enteromopha linza was extracted at various temperature, the most effective extraction temperature was $40^{\circ}C$ while the temperature was $50^{\circ}C$ for Undaria pinnatifida and $60^{\circ}C$ for Hixikia fusiforme, Sargassum fulvellum, Sargassum kjellmanianum and Codium coarctatum. Bus in case of alcohol soluble extraction, the optimum temperature was $30^{\circ}C$ for Enteromorpha linza and $40^{\circ}C$ for Undaria pinnatifida, Sargassum fulvellum and Porphyra suborbiculata. In the effect of pH on extractability, the maximum extractability of NaCl soluble proteins was obtained at pH 7to 8 and pH 8 to 9 for alcohol soluble protein.

• Korean journal of food and cookery science
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• v.28 no.1
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• pp.51-55
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• 2012

This study was conducted to investigate the physicochemical properties of citrus peel extracts with different hot water extraction and enzymatic hydrolysis conditions. Enzymatic hydrolysis was also employed using Viscozyme L and results were compared with that of optimized hot water extract. Hot water extraction was performed under different parameters; the sample to solvent ratio(1:20, 1:15, 1:10), extraction time(2, 4 hrs), extraction temperature(85, $95^{\circ}C$) and enzymatic hydrolysis(0, 1%) and the subsequent extracts were used for determining their physicochemical properties, such as total yield, total phenolics, total flavonoids, and electron donating ability (EDA). With the increase in the sample to solvent ratio and extraction time, total yield, total phenolics, total flavonoids and EDA increased. But extraction temperature did not significantly affect the hot water extract. As hot water extract was hydrolyzed by the enzyme, total yield and active ingredients increased rapidly. In the result of total yield, total phenolics, total flavonoids and EDA, the activity of enzyme-treated extract was higher than those of enzyme-untreated extract. Based upon the overall hot water extraction efficiency, it was found that 20 times volume or 120 min at a time at $95^{\circ}C$ after enzyme treatment was optimal.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.88-91
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• 2014

In this study, oil as a source of biodiesel from Nannochloropsis oceanica was extracted using organic solvent. The oil extraction yield and efficiency from dry and wet microalgae were investigated. The initial fatty acids content of the N. oceanica was 317.8 mg/g cell showing a high oil content over 30%. The yield from dry microalgae was higher than that from wet microalgae due to the inhibition of water. The yield by chloroform-methanol was the highest and the yield by hexane was the lowest. However, the total fatty acids contents with the chloroform-methanol were 678.7 and 778.2 mg/g oil under dry and wet conditions, respectively. The high oil extraction yield by chloroform-methanol reflected the fact that the extracted oil contained a high level of impurity. The hexane-methanol extraction from dry N. oceanica showed high oil extraction efficiency, 82.6%. The chloroform-methanol extraction under wet condition also showed high efficiency, 88.0%. While the hexane-methanol extraction from dry microalgae is desirable under low drying cost, the chloroform-methanol extraction from wet microalgae is desirable under high drying cost.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1334-1340
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• 2007

Extraction characteristics of solid Cheonggukjang and the functional properties of corresponding extracts were monitored by the response surface methodology (RSM). The maximum extraction yield of 12.08% was obtained under the specific extraction conditions, such as microwave power of 132.40 W, ratio of solvent to sample content of 7.57 g/mL and extraction time of 14.11 min. The maximum electron donating ability (EDA) was found as 33.53% at the conditions of 113.26 W microwave power, 16.39 g/mL of ratio of solvent to sample content and 12.67 min extraction time. The maximum superoxide dismutase (SOD) -like activity was 89.62% under the extraction conditions of 61.82 W, 17.06 g/mL and 9.03 min. Based on superimposition of three dimensional RSM with respect to extraction yield, electron donating ability and SOD-like activity obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of $75{\sim}140W$, ratio of solvent to sample content of $3{\sim}12g/mL$ and extraction time of $1{\sim}11min$, respectively.

• Food Science and Preservation
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• v.14 no.4
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• pp.385-393
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• 2007

Much research is conducted on the biological activities of medicinal herbs, traditional plants, and agricultural products, cultivated in Korea. This study focused on optimization of hot-water extraction methods for such products, by analyzing and monitoring extraction characteristics using a response surface methodology. We found that the total phenolics contents, electron-donating abilities, and nitrite-scavenging abilities of extracts were significantly affected both by the solvent used for extraction, and by the nature of the particular herb or plant under study. The extraction efficiencies of valuable ingredients such as alliin, allicin, and total thiosulfinate, were greatly affected by extraction temperature, but not by extraction time or the solvent used. We elicited a regression formula for each variable. We first entered the optimal values of all extraction conditions giving active ingredients into the model. Next, we entered the optimal values of all extraction conditions favoring the retention of valuable antioxidant characteristics. Finally, we entered processing factors into the model. Overall, the optimal extraction was at $80^{\circ}C$ for 3.5 hr with 8.5 ml of solvent/g of sample. The predicted values of each variable were similar to the actual values.