• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.597-606
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• 1992

Effects of dilution rate, inlet glucose and ammonium chloride concentrations on ,he performance of continuous culture of Alcaligenes eutrQPhus for poly-p-hydroxybutyrate (PHB) production were investigated. When inlet substrate concentrations were maintained constant (inlet glucose concentration = 20 g/l, inlet ammonium chloride concentration = 2 g/l), growth rate of residual biomass and PHB production rate showed its maximum at $0.1h^{-1}$ and $0.06h^{-1}$, respectively, and washout at $0.13h^{-1}$. PHB content decreased from 50% to 25% by increasing dilution rate, while specific PHB production rate increased continuously. Cell mass and PHB concentration gave its maximum values at inlet ammonium chloride concentration of 2 g/l and thereafter decreased, which showed the existence of substrate inhibition by ammonium. When inlet glucose concentration was 30 g/l, cell mass reached its maximum value, while PHB concentration increased continuously. The parameters of kinetic model were evaluated by the graphical and parameter estimation methods. The computer simulation results for the effects of dilution rate, inlet glucose and ammonium chloride concentrations fitted the experimental data very well.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.545-550
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• 2012

A 17-run Box-Behnken design (BBD) was used to optimize the extraction conditions of astaxanthin from shrimp waste. Three factors such as ratio of ethanol to raw material, extraction temperature ($^{\circ}C$) and extraction time (min) were investigated. The adjusted coefficient of determination ($R^2{_{adj}}$) for the model was 0.9218, and the probability value (p=0.0003) demonstrated a high significance for the regression model. The optimum extraction conditions were found to be: optimized ratio of ethanol to raw material 29.7, extraction temperature $49.5^{\circ}C$ and extraction time 59.9 min. Under these conditions, the mean extraction yield of astaxanthin was $17.80{\mu}g/g$, which was in good agreement with the predicted model value. Under these conditions, validation experiments were done and the mean extraction yield of astaxanthin was $17.77{\mu}g/g$, which is in good agreement with the predicted model value.

• The Korean Journal of Rheology
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• v.9 no.4
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• pp.200-205
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• 1997

등방상에서는 폴리파라페닐렌테레프탈아미드(PPD-T)와 히드록시 프로필 셀룰로오 스(HPC)가 비슷한 유변학적 거동을 보였다. 그러나 이방성에서는 네마틱상을 형성하는 PPD-T와 콜레스테릭상(또는 꼬인 네마틱상)을 형성하는 HPC는 상이한 유변학적 특성을 나타냈다. 이방상을 나타내는 임계농도(C*)이상의 농도에서 Herchel-Bulkey 모델에 의해 얻 어진 항복응력을 보면 HPC의 경우 농도에 관계없이 거의 일정한 값을 나타낸 반면PPD-T 의경우에는 농도증가와 더불어 항북응력값이 크게 증가하였다. 또한 PPD-T가 일\ulcorner거으로 HPC보다 큰값의 항복응력을 나타냈다. 진동수 1 rad/s 에서는 PPD-T와 HPCahen 탄성계 수 G＇/2G＂가 농도의 증가와 더불어 증가하엿다. 그러나 100rad/s 에서는 HPCdmlruddn 임계농도이상의 농도에서 농도증가와 더불어 탄성계수값이 단순감소한 반면 PPD-T의 경우 에는 포화농도(B-point)이상의 농도에서 농도증가와 더불어 탄성계수값이 계속적으로 증가 하였다. HPC의 경우 저장탄성률이 변형정도의 영향을 받지 않았으나 PPD-T의 경우에는 저장탄성률이 변형정도에 매우 민감하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.216-218
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• 2010

본 논문에서는 기존의 퍼지 필터링 알고리즘의 문제점을 개선한 퍼지 필터링 기법을 제안한다. 제안된 퍼지 필터링 알고리즘은 컬러 영상에서 R, G, B 채널을 각각 분리한다. 분리된 각 채널에서 마스크 정보를 추출하여 채널에 대한 평균값과 중간값의 명암도를 제안된 퍼지 기법의 소속 함수에 적용하여 소속도를 구한 뒤, 추론 규칙에 적용한다. 그리고 R, G, B 각각의 소속도 값을 이용하여 잡음 가능성 여부를 판별한다. 제안된 퍼지 기법에서 소속 함수 구간은 세 개 구간으로 설정하였다. 잡음이라고 판단되는 경우에는 그 잡음 정도에 따라 중간값이나 평균값을 해당 픽셀 값으로 설정하여 잡음을 제거한다. 제안된 기법을 컬러 영상에 적용한 결과, 제안된 기법이 기존의 퍼지 필터링 기법보다 잡음 제거에 있어서 효과적인 것을 확인할 수 있었다.

• Korean Journal of Plant Resources
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• v.30 no.5
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• pp.535-541
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• 2017

In this study, methanol (CAMe) and ethanol (CAEt) extract of Theobroma cacao L. were tested to see possibility as natural functional cosmetic agent. Cacao extract and cacao extract loaded gel were evaluated for various properties such as antioxidant, antimicrobial, cell viability, anti-inflammatory. Inhibition of nitric oxide production in lipopolysaccaride (LPS) stimulated raw 264.7cells, at concentration of $0.125{\sim}1{\mu}g/ml$ a dose-dependent manner. Gel formulation (3% extract) were stable for 60day in both extract. In conclusion, gel containing extract of Theobroma cacao L. indicated strong possibility for functional cosmetic ingredient.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.796-801
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• 2005

For usage of natural antioxidants, sanjook (Sasa boreails var. chiisanensis) leaves were extracted with methanol and investigated about its antioxidative activities and stability. It showed that the antioxidant activity of methanol extracts from the leaves of sanjook depend on their concentration within range of 0.1 to 0.8 mg/ml. The methanol extracts from the leaves of sanjook represented $583{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $800{\mu}g/ml$for $IC_{50}$ of SOD-like activity and $38{\mu}g/ml$for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, while BHT, as a compared substance, was $271{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $680{\mu}g/ml$ for $IC_{50}$ of SOD-like activity and $30{\mu}g/ml$ for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, respectively. The anti-au-toxidation effect for methanol extracts from the leaves of sajook was $55\∼60\%$ within range of 0.1 to 0.8 mg/ml. The pH stability on methanol extracts from the leaves of sanjook was most stable at pH 6. The more acid or akali it became, the more unstable it turned. The thermostability on methanol extracts from the leaves of sanjook remained above $80\%$ of their DPPH activity at range of $0^{\circ}C{\;}to{\;}120^{\circ}$.

• Food Science and Preservation
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• v.21 no.3
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• pp.341-349
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• 2014

The antioxidative effect and quality characteristics of different drying methods (hot air drying, far-infrared radiation drying, vacuum freeze drying) from Schizandra Chinensis Baillon were investigated. The moisture contents and water activity(Aw) contents each 4.46% and 0.38 values of the vacuum freeze drying were lower than those of other samples. A significant not difference in pH values occurred in all samples (p<0.05). The highest content $^{\circ}brix$ vacuum freeze drying was $6.60^{\circ}Brix$ respectively. The turbidity values of the samples were hot air drying 8.24 T%, far infrared radiation drying 0.32 T%, vacuum freeze drying 71.85 T%. The Hunter's L, a and b values of vacuum freeze drying were higher than those of other samples. The order of the free sugar content was glucose>fructose>sucrose, and that of the total free sugar contents were vacuum freeze drying (6.33 g/100 g) > far infrared drying (5.01 g/100 g) > hot air drying (3.73 g/100g). Antioxidant acitivy (DPPH radical scavenging, ABTS radical scavenging) and total phenol, total flavonoid, and total tannin content was highest in vaccum freeze drying than other different drying methods except nitrite scavenging ability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.771-777
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• 2016

Accurate food composition data are essential for calculation of nutrient intake of a population based on its consumption statistics. In the Korean food composition database, there is a lack of reliable analytical data for tocopherols and tocotrienols. Therefore, this study was conducted to provide information on contents on vitamin E in agricultural processed foods in Korea. Tocopherols and tocotrienols were determined by the saponification extraction method followed by high performance liquid chromatography. Analytical method validation parameters were calculated to ensure the method's validity. Samples were obtained in the years of 2013 and 2014 from the Rural Development Administration. The samples included 34 grains and grain products, 14 snacks, 25 fruits, 5 oils, and 11 sources and spices. All vitamin E isomers were quantitated, and the results were expressed as ${\alpha}$-tocopherol equivalent (${\alpha}-TE$). ${\alpha}-TE$ values of cereal and cereal products, snacks, fruits, oils and sauces and spices ranged from 0.03 to 17.53, 1.01 to 12.84, 0.01 to 1.52, 1.09 to 8.15, and 0.01 to $27.53{\alpha}-TE/100g$, respectively. Accuracy was close to 100% (n=3). Repeatability and reproducibility were 2.04% and 4.69%, respectively. Our study provides reliable data on the tocopherol and tocotrienol contents of agricultural and processed foods in Korea.

• Journal of Conservation Science
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• v.25 no.4
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• pp.465-471
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• 2009

In this study, the substitution fumigation gases (15% Ethylene Oxide + 85% HFC 134a, 20% Ethylene Oxide + 80% $CO_2$, 99% Sulfuryl Fluoride + 1% Inert Gas) were applied on the metal, pigment, fabric and paper specimen. The result of the fumigation treatment with 15% Ethylene Oxide + 85% HFC 134a (200g/$m^3$, 48hours) is the color changes (${\Delta}E$) of 1st and 2nd Cu specimens showed significant difference as 3.40, 4.17. On the other hand, other specimens except for Cu showed less than 3.0 in chrominance values. The result with 20% Ethylene Oxide + 80% $CO_2$ (150g/$m^3$, 48hours) is that the color changes (${\Delta}E$) of 1st and 2nd specimens were overall less than 3.0 so that color differences were subtle and hardly recognized with naked eyes. So it is proved that the fumigation treatment with Ethylene Oxide 20% + $CO_2$ 80% is relatively stable on materials in this study. In the case of 99% Sulfuryl Fluoride + 1% Inert Gas (50g/$m^3$, 48hours), the color difference of Lead red ($PbO_4$) of pigment was more than 3.0 that was compared with contrast specimens. But chrominance values in the other specimens were less than 3.0 on average.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.680-689
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• 2016

The present study evaluated the validation method for isoflavone contents of fermented soybean extracts by bioconversion as well as their antioxidant activities. Our results show that the total isoflavone contents of non-fermented and fermented soybean extract ranged between 119.8 to $637.7{\mu}g/g$ and between 567.3 to $2,074.6{\mu}g/g$, respectively. Moreover, fermented soybean extracts had higher contents of isoflavone aglycones, including daidzein, glycitein, and genistein than non-fermented soybean extracts as well as lower contents of isoflavone glucosides such as daidzin, glycitin, and genistin. FRAP and ORAC values ranged between 0.15 to 0.22 and between 195.24 to $753.79{\mu}M$ Trolox equivalents/g in non-fermented and fermented soybean extracts, respectively. These results indicate that fermented soybean extracts had higher total isoflavone contents and antioxidant activities than non-fermented soybean extracts. Bioconversion process in this study may have the potential to produce isoflavone-enriched natural antioxidant agents with high added value from soybean matrices.