• Journal of the Korean Society of Food Culture
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• v.34 no.3
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• pp.361-368
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• 2019

The purpose of this study was to establish the best optimized extraction condition for the optimal development of fresh maca beverage using low temperature extraction and enzyme treatment. Low temperatures were applied to prevent heat-related nutritional loss during the extraction process. Best extraction conditions were investigated based on the ratio of maca to water, the ratio of enzymes, extraction temperature and time, and agitation. The optimal enzyme conditions were also examined after the treatment of cellulase:pectinase mixture to maintain the original color and flavor, as well as to increase the extraction yield. When cellulase:pectinase was 1:1, the extraction rate ranged from 77.84 to 79.29%. In addition, the best extraction rate was found when maca was mixed with twice volume of water and incubated at $45^{\circ}C$ ($84.05{\pm}0.32%$) with 90 rpm ($87.13{\pm}0.46%$) agitation for 3 hours ($84.73{\pm}0.29%$). Furthermore, sensory evaluation showed a high score in flavor, sweetness, and overall acceptability after adding 3% jujube concentrate into a fresh maca beverage.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.63-70
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• 2000

The effect of combinations of temperature, water column height and extraction time onthe efficiency of wet funnel extraction methods for enumerating Enchytraeids in a blanket bog peat soil from Moor House, Cumbria, England were investigated. The optimal conditions for extracting enchytraeids from this study were found to be a water surface temperature of 35$^{\circ}C$, with an extraction time of 6 hours, regardless of initial water temperature and water level in the extraction funnel. The original O'Connor method (40-45$^{\circ}C$ for 3 hours extraction and gradually increasing heating) yielding a high variation in the extraction efficiency, largely due to the comparatively higher temperature and shorter extraction time than this method. Attempts to extract without heat over longer periods showed very low extraction efficiencies for this highly organic blanket bog soil when compared with any of the heating wet funnel methods.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.329-333
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• 2021

Subcritical water extraction (SWE) is an eco-friendly extraction method that uses only purified water as a solvent under high temperature and high pressure conditions. In this study, total phenolics, and antioxidant activity were evaluated in Ziziphus jujuba Mill extracts from subcritical water obtained by varying the extraction temperature (110-190℃) and extraction time (1-20 min). Total phenolics was maximized with extraction at 190℃ for 15 min (67.79±3.45 mg gallic acid equivalent/g jujube). The 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (48.84±4.74%) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging activity (84.75±1.15%) were maximal at extraction conditions of 190℃, for 20 min. All jujube extracts prepared using SWE had higher total phenolics and antioxidant activities than extracts prepared using organic solvent extraction (60℃, 120 min), including methanol and ethanol. SWE could be an excellent alternative to organic solvents for extracting phenolics and antioxidant compounds.

• Food Science and Preservation
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• v.20 no.4
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• pp.592-596
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• 2013

To stabilize the basal extraction conditions of Leonuri herbal products, three kinds of Leonurus sibiricus water extracts were prepared with different extraction conditions (boiling extraction (I), high thermal process & boiling extraction (II), and wet grinding & boiling extraction (III)), and their physiological properties were investigated. The extraction yields of the L. sibiricus water extracts were from 13.02 to 15.90%, with no significant difference among them. The polyphenol contents were significantly high in extracts (II) and (III) than in extract (I). The $IC_{50}$ for the electron-donating ability was the smallest in extracts (II), (III) and (I) in ascending order. The ABTS radical scavenging ability was significantly higher in extracts (II) and (III) than in extract (I). Also, the ACE in hibition ability for 5 mg/mL of each extract was high in extracts (II) and (III), but there was no significant difference among the three extracts in terms of their nitrite scavenging abilities. Extraction processes (II) and (III) were shown to be useful for preparing Leonurus sibiricus water extracts with healthful properties.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1265-1274
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• 2012

This study was conducted to investigate the extraction characteristics including total polyphenol compound content (TPC) and the antioxidative effect of Rumex crispus root extract on commercial corn oil. Extraction yield was increased with extraction temperature but decreased with extraction ratio. No significant differences in aromatics content were found among the extracts prepared with various extraction conditions; extraction ratio, extraction temperature, extraction pH and composition of extractant. Total flavonoid content of the extract was increased with extraction temperature and extraction pH, and highest value of it was found when extractant composition of ethanol in water was 75%. Total polyphenol compound content (TPC) of the extract with 10 fold extraction ratio showed the highest value, but no significant difference in TPC was found with extraction temperature. Reducing power and DPPH (${\alpha}$,${\alpha}$-diphenyl-${\beta}$-picrylhydrazyl) radical scavenging ability (RSA) of the extract in spectrophotometric absorbance were decreased with extraction ratio but increased with extraction temperature and showed 63.1%~98.4% and 67.6%~86.7% of those of ascorbic acid in reducing power and DPPH RSA, respectively. The antioxidative effects of the extract on corn oil were 84.8~93.0% of that of commercial butylated hydroxytoluene, the antioxidant index value was highest when the ethanol composition to water in extractant was equal ratio.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2488-2492
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• 2010

A method is described for the determination of the Po nuclides in a water sample. After the Po nuclides were purified from interfering elements in a water sample using a manganese dioxide precipitation followed by a solvent extraction method, the Po nuclides were deposited onto the silver plate. A large volume of the water sample was effectively pretreated with manganese dioxide precipitation method. To determine the optimum conditions for plating Po, the effects of the pH, volume, temperature and time on the Po deposition were investigated in hydrochloric acid solution. The investigated determination method of Po nuclides with solvent extraction was applied to a tap water sample.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.491-501
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• 2002

A cross-examination between KT&G Central Research Institute and Guangzhou Institute for Drug Control was carried out in order to select optimum conditions for extraction, separation and determination of ginsenosides in red ginseng and to propose a better method for the quantitative analysis of ginsenosides. The optimum extraction conditions of ginsenosides from red ginseng were as follows: the extraction solvent, $70\%$ methanol; the extraction temperature, $100^{\circ}C;$ the extraction time, 1 hour for once; and the repetition of extraction, twice. The optimum separation conditions of ginsenosides on the SepPak $C_{18}$ cartridge were as follows: the loaded amount, 0.4 g of methanol extract; the washing solvents, distilled water of 25 ml at first and then $30\%$ methanol of 25 ml; the elution solvent, $90\%$ methanol of 5 ml. The optimum HPLC conditions for the determination of ginsenosides were as follows: column, Lichrosorb $NH_2(25{\times}0.4cm,$ 5${\mu}m$, Merck Co.); mobile phase, a mixture of acetonitrile/water/isopropanol (80/5/15) and acetonitrile/water/isopropanol (80/20/15) with gradient system; and the detector, ELSD. On the basis of the optimum conditions a method for the quantitative analysis of ginsenosides were proposed and another cross-examination was carried out for the validation of the selected analytical method conditions. The coefficient of variances (CVs) on the contents of ginsenoside-$Rg_{1}$, -Re and $-Rb_1$ were lower than $3\%$ and the recovery rates of ginsenosides were $89.4\~95.7\%,$ which suggests that the above extraction and separation conditions may be reproducible and reasonable. For the selected HPLC/ELSD conditions, the CVs on the detector responses of ginsenoside-Rg, -Re and $-Rb_1$) were also lower than $3\%$, the regression coefficients for the calibration curves of ginsenosides were higher than 0.99 and two adjacent ginsenoside peaks were well separated, which suggests that the above HPLC/ELSD conditions may be good enough for the determination of ginsenosides.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.600-627
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• 2016

Korea is one of the countries with a large veterinary antibiotics market, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. The Korean government started to take interest in estimating the effects of livestock manure on rivers and agricultural soils and in monitoring of heavy metals, organic pollutants and antibiotics in the ambient water and soil. In this paper, pre-treatment methods to separate the selected antibiotics from solid samples were reviewed. It is essential to select an efficient and appropriate procedure for pre-treatment due to the high proportion of proteins and organics in biosolid samples. Pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/basic conditions depending on the compound. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the ${\beta}-lactams$ are easily decomposed in acidic and basic conditions, they were extracted in neutral pH. Filtration with a membrane (pore size, $0.2{\mu}m$) or solid phase extraction with HLB and methanol, as eluents, was normally applied for the clean-up. At least, three different pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.

• Korean Journal of Medicinal Crop Science
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• v.21 no.2
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• pp.97-104
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• 2013

The objective of this study is to investigate the optimal condition for macerating enzymatic extraction process that leads to the highest yield and the largest extracted amount of bio-active contents from Rubus coreanus Miq. fruit. The optimal extraction conditions were found as the following: The initial amount of the water added to the fruit was 20 ~ 30% by weight. The mixing ratio used for the macerating enzyme was 4 : 1 : 2 (w : w : w) for cellulase:pectinase:amylogucosidase, and the amount of the macerating enzyme added was 2% by weight. The extraction process was done at a temperature of $45{\sim}50^{\circ}C$ for 10 hours. The extraction yields on Rubus coreanus Miq. fruit by macerating enzymatic extraction process was increased by 84.3% compared to that of hot-water extraction process. The amounts of organic acids and vitamin found in the extract were also higher. The amount of polyphenol and anthocyanin contents in the extract were 185% and 257% of those from hot-water extraction, respectively. These results suggest that macerating enzymatic extraction is an effective method to boost extraction yield and to increase the amount of extraction of bio-active contents from Rubus coreanus Miq. fruit.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.310-314
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• 2016

The search for natural antioxidants as alternatives to synthetic products is growing. Microalgae have emerged as a source of natural antioxidants with significant and diverse health-promoting properties. In this study, the effects of hot-water extraction conditions on total polyphenol compounds (TPC) production were investigated for lipid extracted microalgae (LEA). In order to enhance the polyphenol productivity, the extraction variables including solvents, temperature, time and ethanol concentration were optimized. The results showed hot-water extraction provided a higher extraction efficiency than the organic solvents and extraction at high temperatures showed a better extraction efficiency. While hot-water extract showed a higher extraction efficiency compared to 98% ethanol extraction, the mixture of water and ethanol (40:60 v/v) showed the highest production of polyphenols. The maximum polyphenols of 3.35 mg GAE (gallic acid equivalent)/g DM were obtained at the optimized extraction time of 10 min, $100^{\circ}C$ and 40% ethanol, respectively. Although Tetraselmis KCTC 12236BP was preprocessed by hexane to remove lipid for bio-diesel production, the results showed LEA contains relatively high level of polyphenols compared to untreated microalgae which can be used in the production of value-added materials. The predictions obtained from the developed Peleg's model were compared with the experimental data under the same operating conditions. The predicted and experimental data were consistent, indicating the reliability of the model.