• 호남수학학술지
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• 제31권4호
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• pp.579-590
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• 2009

The precise form of singular functions, singular function representation and the extraction form for the stress intensity factor play an important role in the singular function methods to deal with the domain singularities for the Poisson problems with most common boundary conditions, e.q. Dirichlet or Mixed boundary condition [2, 4]. In this paper we give an elementary step to get the singular functions of the solution for Poisson problem with Neumann boundary condition or Robin boundary condition. We also give singular function representation and the extraction form for the stress intensity with a result showing the number of singular functions depending on the boundary conditions.

• 생명과학회지
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• 제10권2호
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• pp.202-209
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• 2000

The factors affecting chemical composition of green tea (Camellia sinensis L.) during extraction process were temperatures and times. The optimum extraction conditions were measured in relation to the changes of chemical compositions from water extracts of green tea (Camellia sinensis L.) under different extraction temperatures (50, 70, 9$0^{\circ}C$) and extraction times (1, 3, 5 minute). The change of color intensity during browning reaction, flavonoid components, contents of total phenols and hydrogen donating activity (reducing activity for $\alpha$, $\alpha$'-diphenyl-$\beta$ -picryhydrazyl) of water extracts form green tea increased as extraction temperatures increased from 50 to 9$0^{\circ}C$ and extraction times prolonged from 1 to 5 min. The contents of important free sugars such as sucrose and glucose slightly increased as the extraction time was prolonged, while little difference in the content of fructose with the prolonged extraction time. Catechins contents extracted from the commercial steamed green tea were increased at higher temperature and longer extraction time. Epigallocatechin (EGC) extracted from 9$0^{\circ}C$ (extraction time 5 min). presented 99.9 mg/g in highest composition of catechin followed by epigallocatechin gallate (EGCg), epicatechin (EC), epicatechin gallate (ECg). The content of vitamin C extracted from green tea was increased about 2 times as the extraction temperature increased from 50 to 9$0^{\circ}C$ and as the extraction time increased from 1 to 5 min. with exception at 9$0^{\circ}C$(extraction time:5 min) which showed less vitamin C content than 7$0^{\circ}C$(extraction time : 3 min) probably due to possible destruction of vitamin C by high temperature.

• 한국식품영양과학회지
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• 제35권3호
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• pp.262-270
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• 2006

볶음 처리한 새송이버섯의 환류추출조건에 따른 추출물의 생리기능적 특성을 살펴보았다. 에탄올농도에 따라서는 50% 에탄올농도로 추출하였을 때 총 페놀성 화합물 함량 및 수소공여능이 높은 것으로 나타났으며, 75% 에탄올농도로 추출하였을 때 SOD유사활성이 높은 것으로 나타났다. 아질산염 소거능의 경우에는 에탄올농도가 낮을수록 높은 것으로 나타났다. 추출시간이 증가할수록 수소공여능은 감소하는 것으로 나타났으며, SOD유사활성 및 아질산염 소거능은 증가하는 것으로 나타났다. 추출온도가 증가할수록 수소공여능 및 SOD 유사활성은 감소하는 것으로 나타났으며, 아질산염 소거능은 큰 차이를 보이지 않았다. 용매에 대한 시료량이 증가할수록 수소공여능, SOD 유사활성 및 아질산염 소거능이 감소하는 것으로 나타났다. 이상의 결과를 바탕으로 하여 볶음 처리한 새송이버섯의 추출조건 설정에 활용될 수 있으리라 사료된다.

• Natural Product Sciences
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• 제27권3호
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• pp.187-192
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• 2021

Cordycepin is a characteristic bioactive compound of Cordyceps militaris with various beneficial effects. Cordyceps grows on both grains and insects, and the content of cordycepin varies depending on the cultivation conditions. In this study, the effect of culture conditions on the cordycepin content was analyzed and the extraction conditions were optimized. Analysis of cordycepin content in Pupae-Cordyceps found that it was highly affected by temperature in culture conditions. In the case of mycelium, it grows well at 20 and 25 ℃, but not at 30 ℃. However, the content of cordycepin was highest at 30℃ and less at 20 ℃. The fruiting body also showed a similar tendency: growth was 20 ℃ > 25 ℃ > 30 ℃, but the cordycepin content was 30 ℃ > 25 ℃ > 20 ℃. The content of cordycepin decreased after the fruiting bodies were produced. Next, extraction conditions such as solvent and time were optimized for maximum cordycepin content using response surface methodology (RSM). There was a large difference in the content of cordycepin according to the content of ethanol and the extraction temperature. Through RSM, it was confirmed that the optimum condition for extraction of cordycepin was 48.9 ℃ using 49.0% ethanol, and 160.9 mg/g extract could be obtained under this condition. In conclusion, this study suggested the optimized conditions for the cultivation and extraction of Pupae-Cordyceps for maximizing the content of cordycepin, and this may be applied to the discovery of materials using cordycepin.

• 한국응용과학기술학회지
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• 제38권6호
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• pp.1699-1708
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• 2021

고품질의 아가콩 음료개발을 위해 반응표면분석법에 의한 추출조건을 최적화 하였다. 아가콩의 최적 볶음조건은 250 ℃, 30분으로 설정하였다. 추출시간, 추출온도에 따른 아가콩의 품질지표인 pH, 색도 및 이소플라본 함량은 1% 이내에서의 유의적인 영향을 미치는 것으로 나타났다. 추출온도와 추출시간이 길어질수록 이소플라본 함량은 높은 것으로 나타났다. 반응표면분석의 이소플라본 추출 공정 최적화 결과 추출온도는 99.5 ℃, 추출시간은 1.7 h으로 나타났으며, 이 조건에서 이소플라본의 최적 수율은 10.63 ㎍/mL로 예측되었다.

• 펄프종이기술
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• 제48권1호
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• pp.93-99
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• 2016

The extraction efficiency depending on the extracting methods and the conditions of extraction was investigated. The common steam extraction was compared to the distillation extraction method. The effects of the samples size and the extraction time on the extract yield were also investigated by using UV-Vis spectrophotometer. One of the functional components of pine needle extract as the natural phenol base components were detected by the UV-VIS at around 235 nm wavelength range. The absorbance intensity at around 235 nm wavelength of the pine needle extract was used as the indicator of the extraction efficiency in this experiment. The distillation extraction showed the higher extract yield than the steam extraction. The grinding treatment of pine needles also resulted in the better extract performance, but the severe grinding showed a little decrease in the extract yield especially in case of the distillation extraction method. More than half of the extract was collected at the first stage of the extraction, that was the first 15 minutes in the total 60 minutes extraction.

• 한국식품영양학회지
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• 제12권2호
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• pp.119-123
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• 1999

Test of the optimum condition of solid phase micro extraction(SPME) was performed by use of 5 vol-atile components in dilute aqueous solution. Volatile components of Sancho(Zanthoxylum schinifolium) were isolated by SPME method and were analyzed by GC/MSD and compared with volatile compone-nts isolated by simultaneous distillation extraction (SDE) method. Total 31 components were identified by comparing gas chromatography retention time and mass spectral data. The major compounds were limonene geranyl acetate $\beta$-phellandrene phellandral mycene linalool rose oxide caproic acid and caprylic acid SPME sampling procedure was found to be a good method for qualitative analysis of the volatile components.

• Journal of Applied Biological Chemistry
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• 제63권3호
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• pp.197-201
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• 2020

In order to enhance the extraction efficiency of flavonoid from Saururus chinensis, carbohydrate-hydrolyzing enzyme Viscozyme L aided extraction techniques have been studied. Then flavonoid composition, as well as quercetin, were also identified using UV/Vis, HPLC/MS, and ¹H-NMR. The results showed that favorable extraction conditions were Viscozyme L concentration of 0.25 mg/g, pH 4.2, reaction at 45 ℃ for 12 h. Under the favorable extraction condition, total flavonoid yield (37.9 mg/g) and quercetin yield (0.86 mg/g) increased by about 2.0 and 9.6 times, respectively, compared to control group. Interestingly, as a significant flavonoid of S. chinensis, flavonoid glycones rutin was hydrolyzed to aglycones quercetin by Viscozyme L. These findings provide scientific and theoretical support for the development quercetin-rich products, which was quickly absorbed by the human body than rutin.

• 대한금속재료학회지
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• 제46권12호
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• pp.823-829
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• 2008

The solvent extraction process for the recovery of vanadium from leaching solution of SCR(selective catalytic reduction) spent catalyst was investigated by using Alamine336 as an extractant. The effects of experimental conditions, such as initial pH and concentration of sulfate ion, and ammonia concentration of stripping solution were studied. The extraction percentage of vanadium were increased with the increase of initial pH of leaching solution and decreased with the increase of sulfate ion. More than 99% of vanadium in leaching solution were extracted and stripped at the A/O ratio of 1.0 in 2 stages. On the basis of these results, an optimum solvent extraction process which vanadium was effectively recovered from SCR spent catalyst was proposed.

• 한국응용과학기술학회지
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• 제30권4호
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• pp.612-621
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• 2013

지질 함량이 많은 식품에 방사선 조사여부 판별방법으로 적용가능한 hydrocarbons법의 전처리 추출공정을 개선하고자, 추출시간을 효율화 하고 추출용매의 사용을 줄일 수 있는 마이크로웨이브 추출법을 적용하였다. 국제 교역량이 가장 높은 농산물중 대두를 대상으로 방사선 조사(4 kGy)를 하여 hydrocarbons 분석에 대한 전처리 조건을 최적화하고자 하였다. 예측된 대두의 최적 추출범위는 extraction time 1.3-3.2분, microwave power 61-133 W로 나타났고, 예측된 범위에서 임의점을 설정하여 회귀식에 대입하여 최적값을 예측하였을 때 값은 microwave power와 extraction time이 각각 97 W과 2.2 분으로 확인되었다. 방사선조사 허가식품에 대해서 검지법의 분석결과의 정확성과 더불어 신속성이 요구되는 상황에서 hydrocarbons검지법 적용이 가능한 대두를 대상으로 MAE (micarowave-assisted extraction) 추출법을 적용한다면, 식품공전상의 현행 추출전처리(12-24시간)에 따른 분석시간을 줄이고 추출공정 개선이 가능할 것으로 본다.