• Natural Product Sciences
• /
• v.19 no.2
• /
• pp.166-172
• /
• 2013

Caffeine and epigallocatechin gallate (EGCG) are major constituents of green tea, the leaves of Camellia sinensis (Theaceae). Although EGCG is well known for diverse beneficial effect, caffeine is sometimes harmful with adverse effects. Therefore, the extraction efficiency was investigated using different extraction method such as extraction solvent, extraction time, extraction method, and repeated extraction. The content of EGCG and caffeine in green tea extract was quantitated by HPLC analysis. The extraction condition exerted difference on the extraction yield. The content of EGCG was also affected by different extraction condition. Especially, the extraction solvent greatly affected the content of EGCG in the extract. However, the content of caffeine was less affected compared to that of EGCG. The inhibitory effect of green tea extract on pancreatic lipase was almost similar regardless of extraction condition. Taken together, optimization of extraction condition will provide best efficacy for further development of green tea as anti-obesity therapeutics.

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

• The Korean Journal of Food And Nutrition
• /
• v.32 no.5
• /
• pp.504-510
• /
• 2019

The purpose of this study was to compare the effects of soaking and ultrasonic extraction by observing the change of contents with extraction time of physicochemical properties (solid content, colorness, caffeine, chlorogenic acid, total polyphenols, DPPH, and ABTS). As a result of the analysis, solid content increased with longer extraction time and the whiteness tended to decrease with longer extraction time. Conversely, the extraction of functional materials showed a tendency to increase as the extraction time increased. Caffeine reached the maximum value after two hours soaking, but showed the same result as one hour for sonication. Chlorogenic acid did not show difference from the content of coffee extracted for one hour soaking only by sonication extraction for 30 minutes. The total polyphenols eluted with approximately two hours of soaking even after 30 minutes of sonication. DPPH and ABTS were insignificant in their concentrations, but their antioxidative effect was more than two hours of soaking with only 30 minutes of sonication. Sonication has a short time extraction from a functional aspect (caffeine content, chlorogenic acid, polyphenol content, and antioxidant capacity) and this experiment can provide basic data for the development of innovative recipes.

• Journal of the Korean Society of Food Culture
• /
• v.11 no.3
• /
• pp.385-392
• /
• 1996

The soluble solid of red pepper was extracted by water in order to investigate changes of soluble solid content by different extraction temperature $(4{\sim}90^{\circ}C)$ and time $(1/2{\sim}3\;hrs)$, and the contents of carotenoid, capsaicinoids, free sugar, organic acid, free amino acid in soluble solid were measured. Most of soluble solid in red pepper was extracted within the first 2 hrs and $93{\sim}98%$ of total soluble solid was extracted during the first 30 min. The contents of carotenoid increased by increasing extraction time and temperature, but decreased by increasing extraction time at $60^{\circ}C$ and $90^{\circ}C$. ${\beta}$-carotene content was sharply decreased after 2 hrs at $90^{\circ}C$. The content of capsaicinoid was sharply increased between 1 hr and 2 hr. Fructose and glucose in red pepper were extracted in the range of $83.8%{\sim}96.4%$ and the contents of free sugar gradually increased by increasing extraction time and temperature. The content of organic acid was gradually increased by increasing extraction time and temperature and the greatest amount of organic acid was extracted during the first 30 min of extraction time. The content of free amino acid was decreased by increasing extraction temperature.

• Korean Journal of Medicinal Crop Science
• /
• v.24 no.4
• /
• pp.263-270
• /
• 2016

Background: In this study, microwave extraction was used, which is an effective method to extract useful bioactive substances as it requires low quantities of solvent and short time periods. The aim of this study was to determine the optimal extraction conditions for Agrimonia pilosa Ledeb. Methods and Results: The independent variables were ethanol concentration, microwave power, and extraction time, each of which had five levels. The dependent variables were total polyphenol and total flavonoid content, and DPPH radical scavenging activity. To determine the optimal extraction conditions for bioactive compounds, a response surface methodology was employed. Contour maps were generated from polynomial equations. The optimal conditions were then assumed by superimposing these contour maps. Based on the resulting graph, the optimal microwave extraction conditions for Agrimonia pilosa Ledeb were determined as 42 - 48% ethanol concentration, 240 - 280W microwave power, and 13 - 20 min of extraction time. Conclusions: Ethanol concentration had a significant effect on microwave extraction, in terms of total polyphenol and total flavonoid content, as well as DPPH radical scavenging activity. Microwave power and extraction time influenced the total polyphenol content, but not the total flavonoid content or the DPPH radical scavenging activity.

• Food Science and Preservation
• /
• v.9 no.3
• /
• pp.332-337
• /
• 2002

This study was undertaken in order to compare reflux extraction(RE) and microwave-assisted extraction(MAE) in extraction efficiency and establish optimum microwave extraction conditions in obtaining Ligularia fischeri extracts. A considerable reduction in extraction time was accomplished by MAE. When 70% methanol 50% methanol 70% ethanol, or 50% ethanol was used, MAE extract contained equal levels of soluble solid and total polyphenol as obtained by RE. The optimum microwave-assisted extraction conditions for Ligularia fischeri were achieved by 120∼150 watts of microwave energy and 4∼8 minutes of extraction time. No significant changes were found in antioxidant activity with DPPH scavenging method over the variation of microwave energy or extraction time. The use of diluted methanol or ethanol improved soluble solid content(30%), total polyphenol content(2.7%) and antioxidant activity(68%).

• Food Science and Preservation
• /
• v.11 no.1
• /
• pp.88-93
• /
• 2004

This study was conducted in order to compare reflux extraction(RE) and microwave-assisted extraction(MAE) in extraction efficiency and establish optimum microwave extraction conditions in obtaining Aster scaber Thunb extracts. Extraction time was reduced considerably in MAE. When 70％ methanol, 50％ methanol, 70％ ethanol, or 50％ ethanol was used, no difference was found in the amount of soluble solid and total phenol between MAE and RE. The optimum microwave-assisted extraction conditions for Aster scaber Thunb were achieved by 120-150 watts of microwave energy and 4∼8 minutes of extraction time. No significant changes were found in antioxidant activity using DPPH scavenging method over the variation of microwave power or extraction time. The use of diluted methanol or ethanol improved soluble solid content(30.8％), total polyphenol content(2.9％) and antioxidant activity(69％ ).

• Journal of KIISE
• /
• v.44 no.6
• /
• pp.581-586
• /
• 2017

For automatic web scraping, unnecessary components such as menus and advertisements need to be removed from web pages and main contents should be extracted automatically. A content block tends to be located in the middle of a web page. In particular, Korean web documents rarely include metadata and have a complex design; a suitable method of content extraction is therefore needed. Existing content extraction algorithms use the textual and structural features of content blocks because processing visual features requires heavy computation for rendering and image processing. In this paper, we propose a new content extraction method using the tag positions in HTML as a quasi-visual feature. In addition, we develop a tag rank position, a type of tag position not affected by text length, and show that gradient boosting with the tag rank position is a very accurate content extraction method. The result of this paper shows that the content extraction method can be used to collect high-quality text data automatically from various web pages.

• ETRI Journal
• /
• v.20 no.3
• /
• pp.272-283
• /
• 1998

In this paper, we propose efficient content-based image retrieval methods using the automatic extraction of the low-level visual features as image content. Two new feature extraction methods are presented. The first one os an advanced color feature extraction derived from the modification of Stricker's method. The second one is a texture feature extraction using some DCT coefficients which represent some dominant directions and gray level variations of the image. In the experiment with an image database of 200 natural images, the proposed methods show higher performance than other methods. They can be combined into an efficient hierarchical retrieval method.

• Korean Journal of Medicinal Crop Science
• /
• v.19 no.4
• /
• pp.271-275
• /
• 2011

In this study, ginseng flower water extracts were analyzed to set up the ginsenoside content and quality optimization condition. The highest total ginsenoside content among the ginseng flower water extracts was 67.44mg/g which was extracted at $85^{\circ}C$ for 3 hours. In addition, the ginsenoside content decreased according to the increased extraction temperature and time. The highest total content of $Rb_2$ and Re was 37.42mg/g at $75^{\circ}C$ for 6 hours. Total content of $Rb_2$ and Re decreased according to the increased extraction temperature and time. The highest prosapogenin ($Rg_2$ + $Rg_3$ + $Rh_1$) content among the total of ginseng flower water extracts was 18.58mg/g which was extracted at $95^{\circ}C$ for 12 hours. The sweetness, absorbance were increased according to the increased extraction temperature and time. But pH was decreased according to the increased extraction time.