• Journal of the Korean Society of Food Culture
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• v.12 no.3
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• pp.265-274
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• 1997

This study was conducted in ordor to find the most suitable conditions for producing the Doenjang with optimal odor compound contents. Three sample groups with the different preparing methods -Doenjang that has not gone through the soy sauce separation process (Doenjang A), Doenjang that has gone through the soy sauce separation process; Meju-20% salt water ratio of 1 : 4 (Doenjang B), and that with the ratio of 1.3 : 4 (Doenjang C)- were tested during different ripening periods. Odor compound contents were analyzed through Solvent Extraction Method and Simultaneous Steam Distillation Extraction (SDE). The number of odor compounds was greatest in Doenjang A and during the mid to late stage in each groups. In the sensory evaluation of Doenjang odors, Doenjang A received the highest scores in the categories of overall preferences, while Doenjang C got the lowest scores. Individual odor didn't vary significantly during ripening periods, but the overall odor and taste preference was highest in the samples ripened for 75 to 120 days. Stepwise multiple regression analysis of major odor compounds of Doenjang revealed that benzeneacetaldehyde is the major explanatory variable for offensive odor. Benzeneethanol, 3-methylthio-propanal and 4-methyl-phenol are the explanatory variables for salty odor, nutty odor and rancid odor, respectively. Odor compounds that contribute to the overall odor preference varied from the compounds that affect the taste preference.

• Preventive Nutrition and Food Science
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• v.11 no.3
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• pp.232-236
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• 2006

The essential oil of Swertia chirata Buch.-Ham. was extracted by solvent extraction (n-pentane:diethylether, 1:1) method using simultaneous distillation-extraction (SDE) apparatus and analyzed by gas chromatography-mass spectrometry (GC/MS). The yield of essential oil obtained from S. chirata was 236.47 mg/kg. Seventy seven compounds of the essential oil belonging to chemical classes of acid (4), alcohol (21), aldehyde (15), ester (3), furan (3), hydrocarbon (7), ketone (17) and miscellaneous (7) were tentatively identified. The major volatile compounds ranged in content order were as follows: undecanoic acid (28.63%), 2-buten-2-one (20.42%), camphor (18.40%), 2-heptadecanone (14.72%), and cedrol (13.07%).

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.635-641
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• 2014

Scutellaria baicalensis $G_{EORGI}$ (Scutellariae Radix) has been used to clear heat and to dry dampness in the stomach or intestines, which manifests as diarrhea or dysenteric disorder. In this study, we investigated the effective preparation of active components in Scutellariae Radix using the methods of solvent extraction and absorption fractionation for the development of new functional food or pharmaceuticals. The marker substances, baicalin, baicalein, wogonoside, and wogonin were directly isolated from the Scutellariae Radix. There chemical structures were elucidated by spectroscopic analysis. The Scutellariae Radix was extracted with hot water. To enhance yield of flavonoids in Scutellariae Radix, the hot water extract was dissolved in ethanol with concentration dependent manner. The precipitates were separated using centrifugal techniques at 10,000 rpm. Supernatant liquid was applied to the HPLC for quantification of major compounds. Separately, the hot water extract was absorbed on Diaion HP-20 resin. And then, the absorbed fraction was eluted with methanol for HPLC. The contents of baicalin, baicalein, wogonoside and wogonin in different treatment methods were analyzed by HPLC. Total amount of four major components were 16.9% in 50% ethanol extract, 21.7% in 70% ethanol extract, 20.5% in 90% ethanol extract, and 39.3% in absorbed fraction of Diaion HP-20 resin. In these results, we found that resin absorption method is suitable for the extraction of enriched flavonoids from Scutellariae Radix.

• Current Photovoltaic Research
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• v.7 no.1
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• pp.21-27
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• 2019

Lifetime of Si photovoltaics modules are about 25 years and a large amount of waste modules are expected to be discharged in the near future. Therefore, the extraction and collection of valuable metals out of discharged Si modules will be one of the important technologies. In this study, we demonstrated that supercritical $CO_2$ extraction method can be effectively used to remove Cu, one of the abundant elements in the module, as well as its oxide form, $Cu_2O$. Especially, we proved that the addition of hexane as co-solvent is effective for the removal of both materials. The optimal ratio of $CO_2$ and hexane was 4:1 at a fixed temperature and pressure of $250^{\circ}C$ and 250 bar, respectively. In addition, it was proven that the removal of $Cu_2O$ was preceded via reduction of $Cu_2O$ to Cu.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.427-434
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• 2009

Analytical method for prochloraz in cabbage, apple, pepper, mandarin, and hulled rice was established by conversion it to 2,4,6-trichlorophenol (TCP). Crop samples were extracted with acetonitrile, and partitioned with dichloromethane. The sample extracts were hydrolyzed with pyridine hydrochloride in a vial by heating for 1 hour, and analyzed with GC-ECD after partitioning with dichloromethane. Method quantification limit (MQL) of prochloraz was 0.01 mg/kg. Recoveries at 0.1 mg/kg level was 105-113% while at 0.5 mg/kg level was 82-87%. In both of the cases CV was less than 10%. Through this procedure soxhlet extraction and refluxing apparatus of conventional method were discarded and simple solvent extraction and small vial were successfully employed, resulting in simple, rapid, economic and more precise method.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.189-195
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• 2004

Rapid and simple method was developed for simultaneous determination of vitamins A and E contents in infant formula. Vitamins A and E were extracted by PDA-HPLC with reversed phase column using organic solvent, and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with results of Food Standards Codex and AOAC method for evaluation of developed method, Vitamins A and E contents in CRM determined by developed method were within certified range of standard values. Developed method has great advantages of simple and rapid sample preparation and simultaneous determination of vitamins A and E by PDA-HPLC using reversed phase column.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.E
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• pp.373-381
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• 1993

To understand the human exposure levels of volatile halogenated hydrocar-bons in ambient air, a new rapid and convenient analytical method for determination of the compounds in gaseous phase was evaluated and established. The method is based upon passsive diffusion to personal sampler containing adsorbent and solvent extraction followed by purge trap/ on-column cryof-ocusing method. A new method needs no special instrumentation for gas collection because it is based upon the passive diffusion principle. The typical chromatogram obtained in this study proved that rapid and simultaneous determination of target analytes was possible with good resolution. The developed method was successfully applied to determine the volatile halogenated hydrocarbons in indoor air and the values obtained by this new method were compared with those by direct suction method. The concentration of carbon tetrachloride, 1,1,2-trichloroethylene, chloroform showed the values below 400$\mug/m^3$ except the maximum of 1,513$\mug/m^3$ of chloroform. 1,1,1-Trichloroethane showed approximately 1,000 to 5,000$\mug/m^3$ range of diurnal fluctuation in indoor air.

• Preventive Nutrition and Food Science
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• v.2 no.3
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• pp.197-201
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• 1997

To develop a rapid analytical method of dimethylamine(DMA) and trimethylamine(TMA) in fish, the contents of DMA and TMA in squid(Illex illecebrosus and Sepiell maindroni), cod(Gadus marcrocephalus) and plaice (Paralichthys olivaceus) by gas chromatographic (GC) and colorimetric method were determined. Recoveries for DMA in fish were 86.8~102.5% by GC and 74.2~94.5% by colorimetric method, while those for TMA were 93.0~101.1% by GC and 62.9~117.5% by colorimetric method. The contents of DMA and TMA in fish by GC were 29.7~325.3mg/kg and 145.6~356.0 mg/kg, respectively, and these by colorimetric method were 20.0~241.2mg/kg and 139.1~304.3mg/kg, respectively. The analysis of DMA and TMA in fishes by GC after the solvent extraction was simpler and faster and showed better recovery than colorimetric method.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.238-241
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• 2010

The purification of indole from 54.3wt% indole fraction (temperature range of distillate: $250{\sim}255^{\circ}C$) recovered by extraction-distillation combination of coal tar fraction (temperature range of distillate: $240{\sim}265^{\circ}C$) was examined by solute crystallization. The feed consists of eight components such as quinoline, iso-quinoline, indole, quinaldine, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl and phenyl ether. Hexane and an aqueous solution of methanol (50 : 50 vol%) were used as the crystallization solvent and the coolant, respectively. A batch stirred tank of glass material was used as a crystallization apparatus. By increasing the operation temperature and the volume ratio of solvent to feed at initial, the purity of indole increas ed, but yields of indole showed a decreasing tendency. Solute crystallization method using hexane as a solvent was excellent because the purity of 99.3 wt% indole was recovered at the yield of 50% without washing operation.

• Journal of Pharmaceutical Investigation
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• v.34 no.4
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• pp.289-297
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• 2004

Acyclovir (ACV) is one of the most effective and selective agents against viruses of the herpes group. Because of low solubility, bioavailability of ACV has shown below 30% with oral dosage form. In our previous study, we reported that the fabrication of solid dispersion of ACV was possible and the solid dispersion of ACV and PVP was the most useful in all samples. In this study, we examined the effect of mixture ratio of polymers (PEG and PVP) to ACV. Solubility of ACV was dramatically increased up to 25 mg/ml in $80^{\circ}C$ distilled water. So water was used as a solvent to eliminate problem of residual solvent. Spray drying method was used for the solid dispersion of ACV as solvent extraction. Different scanning calorimeter was used to check degradation of drug. Polymer carriers were PEG 6,000 and PVP. In summary, ACV-PVP (1:3) showed the best solubility in distilled water.