• Natural Product Sciences
• /
• 제19권2호
• /
• 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.

• 한국환경과학회지
• /
• 제21권10호
• /
• 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.

• 한국식품영양학회지
• /
• 제32권5호
• /
• 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.

• 한국식생활문화학회지
• /
• 제11권3호
• /
• 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.

• 한국약용작물학회지
• /
• 제24권4호
• /
• 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.

• 한국식품저장유통학회지
• /
• 제9권3호
• /
• pp.332-337
• /
• 2002

마이크로웨이브 추출방법과 환류 냉각 추출방법을 비교한 결과, 물과 에탄올의 혼합용매로 추출한 경우 마이크로웨이브 추출 방법에 의하여 추출시간을 단축시키면서 환류 냉각 추출 방법에서와 같은 수준의 가용성 고형분 및 총 폴리페놀 함량을 갖는 곰취 추출물을 얻을 수 있었다. 마이크로웨이브 추출시 최적 마이크로웨이브 에너지는 120∼150 W 였고 추출시간은 4∼8분이 적당하였다. 추출에 사용한 용매들 가운데 에탄올, 메탄올 보다 물 그리고 물과 에탄올 또는 메탄올 혼합용매를 사용한 추출물의 가용성 고형분, 총 폴리페놀 함량 및 항산화 효과가 높은 것으로 나타났다.

• 한국식품저장유통학회지
• /
• 제11권1호
• /
• pp.88-93
• /
• 2004

마이크로웨이브 추출방법과 환류 냉각 추출방법을 비교한 결과, 물과 에탄올의 혼합용매로 추출한 경우 마이크로웨이브 추출 방법에 의하여 추출시간을 단축시키면서 환류 냉각 추출 방법에서와 같은 수준의 가용성 고형분 및 총 폴리페놀 함량을 갖는 참취 추출물을 얻을 수 있었다. 마이크로웨이브 추출 시 최적 마이크로웨이브 에너지는 120∼150 W였고 추출시간은 4∼8분이 적당하였다. 추출에 사용한 용매들 가운데 에탄올, 메탄을 보다 물 그리고 물과 에탄을 또는 메탄을 혼합용매를 사용한 추출물의 가용성 고형분, 총 폴리페놀 함량 및 항산화 효과가 높은 것으로 나타났다.

• 정보과학회 논문지
• /
• 제44권6호
• /
• pp.581-586
• /
• 2017

웹 문서를 자동으로 수집하면 대량의 정보를 손쉽게 모을 수 있다. 이러한 정보 수집 과정을 위해 웹 문서에서 메뉴, 광고 등 불필요한 정보를 제거하고 본문을 자동으로 추출할 필요가 있다. 특히 한국어 웹문서는 영어권과 달리 메타데이터가 포함된 경우가 드물고 디자인이 복잡하여 한국어 웹에 맞는 자동 본문 추출 방법이 필요하다. 기존의 본문 추출 방법은 주로 본문 블록의 문자적, 구조적 특성을 활용한다. 시각적 특성을 처리하기 위해서는 렌더링, 이미지 처리 등에 많은 계산이 필요하기 때문이다. 이 논문에서는 HTML에서 태그 위치를 준-시각적 특성으로 활용한 새로운 본문 추출 방법을 제시한다. 태그 위치는 텍스트의 길이에 따라 가변적이기 때문에 태그 서열 위치라는 특성을 개발하였고, 이를 경사 부스팅과 함께 이용하면 정확한 본문 추출이 가능함을 보인다. 본 논문의 연구 결과는 텍스트 분석에 필요한 양질의 문서 자료를 다양한 형태의 웹페이지에서 자동으로 수집하는 데에 쓰일 수 있다.

• ETRI Journal
• /
• 제20권3호
• /
• 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.

• 한국약용작물학회지
• /
• 제19권4호
• /
• 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.