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Optimization of the ultrasound-assisted synthesis of allyl 1-naphthyl ether using response surface methodology

FERNANDES, Joao Paulo dos Santos; CARVALHO, Bruno Simoes; LUCHEZ, Cibele Venancio; POLITI, Mario Jose; BRANDT, Carlos Alberto
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
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65.85%
Allyl 1-naphthyl ethers are useful compounds for different purposes, but reported methods to synthesize them require long reaction times. In this work, we have obtained allyl 1-naphthyl ether in good yield using ultrasonic-assisted methodology in a 1-h reaction. A central composite design was used to obtain a statistical model and a response surface (p < 0.05; R(2) = 0.970; R(adj)(2) = 0.949; R(pred)(2) = 0.818) that can predict the optimal conditions to maximize the yield, validated experimentally. (C) 2010 Elsevier B.V. All rights reserved.

Produção de bacteriocina por Bifidobacterium lactis a partir de leite desnatado; Bacteriocin production by Bifidobacterium lactis from skimmed milk.

Castillo Martinez, Fabio Andres
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/09/2013 PT
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Existe um número muito limitado de estudos referentes à produção de componentes antimicrobianos ou bacteriocinas produzidas por espécies de bifidobactérias. Nesse âmbito, o objetivo deste trabalho foi avaliar a produção de bifidobacteriocina em leite desnatado (LD). Para tanto, o estudo foi dividido em três etapas. A primeira etapa constituiu na preparação dos meios de cultura Man, Rogosa e Sharpe (MRS), Bifidus Selective Medium (BSM) e LD suplementado com 1% (p/v) de Tween 80 (T80), Inulina (I) ou Extrato de levedura (YE). Nesta etapa, os processos fermentativos foram conduzidos em shaker, nas condições: 50 rpm/37ºC/48h. Foram realizadas análises de pH, concentração de açúcares e ácidos, crescimento celular e determinação da atividade da bifidobacteriocina pelo método de difusão em ágar contra L. monocytogenes. Na segunda etapa, e baseado nos resultados obtidos, foi desenhado um delineamento composto central (CCD) construído a partir dos seguintes parâmetros: temperatura (34, 37, 40 °C) e concentração de YE (0,5; 1,0; 1,5 g/L). Na terceira etapa do trabalho, foram realizados os cultivos em biorreator de 2 L, contendo 10% de leite desnatado, nas seguintes condições: 200 rpm, 36°C, 2,0 g/L de YE, 48h de incubação em anaerobiose. Obteve-se em LD suplementado com YE (1%)...

Cyclodextrin glycosyltransferase production by the Bacillus sp., subgroup alcalophilus using a central composite design

Blanco, K. C.; de Lima, C. J B; de Oliveira, P. A P L V; Pião, A. C S; Contiero, Jonas
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 450-459
ENG
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Cyclodextrin glycosyltransferase (CGTase) activity was produced by the Bacillus sp., subgroup alcalophilus in a culture medium containing cassava starch. A central composite design and response surface methodology were used to study the influence of carbon source (cassava starch), nitrogen sources (yeast extract and tryptone) and sodium carbonate in the production medium. Assays were performed in 300 mL Erlenmeyer flasks containing 100 mL of production medium maintained in a shaker at 150 rpm at 35±1°C for 72 h of fermentation. The independent variables [0.75% cassava starch, nitrogen sources (0.375% yeast extract and 0.375% tryptone) and 1% Na2CO3] produced an enzyme activity of 96.07 U mL-1.© Academic Journals Inc.

Application of response surface methodological approach to optimise Reactive Black 5 decolouration by crude laccase from Trametes pubescens

Roriz, Margarida S.; Osma, Johann F.; Teixeira, J. A.; Rodríguez Couto, S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /09/2009 ENG
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Response surface methodology (RSM) was applied to optimise the decolouration of the diazo dye Reactive Black 5 (RB5) by crude laccase from the white-rot fungus Trametes pubescens. The presence of the redox mediator 1-hydroxybenzotriazole (HBT) greatly improved the decolouration levels of RB5 by crude laccase from T. pubescens. Central composite design (CCD) using RSM with three variables namely redox mediator (HBT), dye (RB5) and enzyme (laccase) concentrations was used in this study to optimise significant correlation between the effects of these variables on the decolouration of RB5. The optimum concentrations of HBT, RB5 and laccase were 1.17 mM, 150 mg/l and 500 U/l, respectively, for a maximum decolouration of RB5 (about 60% in 20 min). A quadratic model was obtained for dye decolouration through this design. The experimental values were in good agreement with the predicted ones and the model was highly significant, the correlation coefficient being 0.965. Interaction between HBT and RB5 concentrations, HBT and laccase concentrations and RB5 and laccase concentrations were negligible. In addition, when the kinetic parameters for RB5 decolouration were calculated according to Hannes–Wolf plot, the following values were obtained: KM of 260.11 mg/l and Vmax 37.59 mg/l min.; Spanish Ministry of Education and Science; Ramón y Cajal Programme and the European Social Fund; Erasmus Rovira i Virgili University (Tarragona...

Sensitive determination of perphenazine in pharmaceuticals and human serum by flow injection chemiluminescence method using [Ru(phen)3]2+-ce(IV) system and a chemometrical optimization approach

Rezaei,B.; Mokhtari,A.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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This paper describes a simple, rapid and sensitive chemiluminescence (CL) method for the determination of perphenazine by flow injection (FI) system. All variables that can affect the CL response were optimized by employing central composite design (CCD) for the experimental design and response surface methodology (RSM) for the modeling. Optimization by means of CCD method with respect to conventional single factor at a time method showed a significant improvement in the sensitivity. Under the optimum experimental conditions, a wide linear relationship between analyte concentration and peak height was obtained within the range 1.2-1,300 ng mL-1 with correlation coefficient of 0.9978. The limit of detection was 0.4 ng mL-1 (S/N = 3) and the relative standard deviation for 6 repeated measurements of a solution containing 70.5 ng mL-1 was lower than 4%. This method was successfully applied for the quantification of perphenazine in pharmaceutical formulations and human serum with good recoveries (95.3-104.0%). Sample throughput was 100 ± 5 samples per hour.

Acid treatments of montmorillonite-rich clay for Fe removal using a factorial design method

Bieseki,Lindiane; Bertell,Francine; Treichel,Helen; Penha,Fabio G.; Pergher,Sibele B. C.
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 EN
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Montmorillonite clays are of great interest for industrial processes such as catalysis and adsorption. The textural properties of clays can be modified in an attempt to increase their uses. This paper describes the acid treatment of natural montmorillonite clay. The materials were characterized using X-ray diffraction (XRD), atomic absorption spectroscopy (AA) and BET surface area measurements. Three different acids (HCl, HNO3 and H2SO4) were tested, and HCl and H2SO4 were more efficient for removing Fe from the clay. The results indicate that HCl better preserves the material structure because less Al is removed. A central composite design (CCD) 2² was applied to evaluate the treatment using HCl. The temperature and concentration presented positive effects on the removal of Fe, Al and Mg. Combinations of the HCl acid solution concentration and temperature, such as 4 mol.L-1/50 °C and 1 mol.L-1/75 °C, assured that Fe was removed with less damage to the structure.

Dye decolorizing potential of a novel fungus Coriolus versicolor ML04 in the medium optimized by response surface methodology

Venil,Chidambaram Kulandaisamy; Lakshmanaperumalsamy,Perumalsamy
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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The potential of the white rot fungus, Coriolus versicolor ML04 to decolorize the widely used textile dye Blue BB was tested by employing statistical optimization. Response surface methodology (RSM) involving a central composite design (CCD) was applied to evaluate the interactive effects of four significant factors in different ranges i.e.; glucose (0.5 - 2.5 g/L), yeast extract (0.4 -1.2 g/L), dye concentration (100 - 500 ppm) and inoculum size (5 - 20 % v/v) to decolorize the Blue BB. The results demonstrated the effectiveness of the statistical experimental design and the ability of C. versicolor ML04 for maximum dye decolorization (>96%) at the optimum conditions of the significant factors.

Scale up of dextran production from a mutant of Pediococcus pentosaceus (SPAm) using optimized medium in a bioreactor

Patel,Seema; Kothari,Damini; Shukla,Rishikesh; Das,Debasish; Goyal,Arun
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
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65.87%
The mutant of Pediococcus pentosaceus (SPAm) produced earlier by UV-mutagenesis exhibiting higher dextransucrase activity as compared to wild-type was used. The generated mutant SPAm gave 12.2 mg/ml, a 20% higher dextran than wild-type. Response surface methodology was carried out for further enhancement of dextran production. To enhance dextran production by the mutant SPAm, Plackett-Burman Design and a 2² full factorial Central Composite Design was employed. After response optimization, the optimum concentration of sucrose and yeast extract was 5.115% (w/v) and 0.635% (w/v), respectively. The experimental values of dextran 36.0 mg/ml at flask level and 35.0 mg/ml at bioreactor level were in good agreement with the predicted value of 40.8 mg/ml. The increase in dextran production by the mutant SPAm using the optimized medium was 3 fold higher as compared to unoptimized medium.

Statistical evaluation of nutritional components impacting phycocyanin production in Synechocystis SP

Deshmukh,Devendra V.; Puranik,Pravin R.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 EN
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65.85%
Alkaliphilic cyanobacterial cultures were isolated from Lonar lake (MS, India). Among the set of cultures, Synechocystis sp, was studied for phycocyanin production. A maximum yield was obtained in BG-11 medium at optimized conditions (pH 10 and 16 h light). In order to increase the phycocyanin yield media optimization based on the eight media components a Plackett-Burman design of the 12 experimental trials was used. As per the analysis CaCl2.2H2O and Na2CO3 have been found to be the most influencing media components at 95% significance. Further the optimum concentrations of these components were estimated following a Box Wilson Central Composite Design (CCD) with four star points and five replicates at the center points for each of two factors was adopted for optimization of these two media components. The results indicated that there was an interlinked influence of CaCl2.2H2O and Na2CO3 on 98% significance. The maximum yield of phycocyanin (12% of dry wt) could be obtained at 0.058 g/l and 0.115 g/l of CaCl2.2H2O and Na2CO3, respectively.

Medium optimization of protease production by Brevibacterium linens DSM 20158, using statistical approach

Shabbiri,Khadija; Adnan,Ahmad; Jamil,Sania; Ahmad,Waqar; Noor,Bushra; Rafique,H.M.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
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65.87%
Various cultivation parameters were optimized for the production of extra cellular protease by Brevibacterium linens DSM 20158 grown in solid state fermentation conditions using statistical approach. The cultivation variables were screened by the Plackett-Burman design and four significant variables (soybean meal, wheat bran, (NH4)2SO4 and inoculum size were further optimized via central composite design (CCD) using a response surface methodological approach. Using the optimal factors (soybean meal 12.0g, wheat bran 8.50g, (NH4)2SO4) 0.45g and inoculum size 3.50%), the rate of protease production was found to be twofold higher in the optimized medium as compared to the unoptimized reference medium.

Optimizing a culture medium for biomass and phenolic compounds production using Ganoderma lucidum

Zárate-Chaves,Carlos Andrés; Romero-Rodríguez,María Camila; Niño-Arias,Fabián Camilo; Robles-Camargo,Jorge; Linares-Linares,Melva; Rodríguez-Bocanegra,María Ximena; Gutiérrez-Rojas,Ivonne
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
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65.85%
The present work was aimed at optimizing a culture medium for biomass production and phenolic compounds by using Ganoderma lucidum. The culture was optimized in two stages; a Plackett-Burman design was used in the first one for identifying key components in the medium and a central composite design was used in the second one for optimizing their concentration. Both responses (biomass and phenolic compounds) were simultaneously optimized by the latter methodology regarding desirability, and the optimal concentrations obtained were 50.00 g/L sucrose, 13.29 g/L yeast extract and 2.99 g/L olive oil. Maximum biomass production identified in these optimal conditions was 9.5 g/L and that for phenolic compounds was 0.0452 g/L, this being 100% better than that obtained in the media usually used in the laboratory. Similar patterns regarding chemical characterization and biological activity towards Aspergillus sp., from both fruiting body and mycelium-derived secondary metabolites and extracts obtained in the proposed medium were observed. It was shown that such statistical methodologies are useful for optimizing fermentation and, in the specific case of G. lucidum, optimizing processes for its production and its metabolites in submerged culture as an alternative to traditional culture.

Optimization of a spectrofluorimetric method based on a central composite design for the determination of potassium losartan in pharmaceutical products

Demirkaya-Miloglu,Fatma; Yaman,Mehmet Emrah; Kadioglu,Yucel
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 EN
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95.93%
Here, a spectrofluorimetric method for the determination of potassium losartan (PL) in pharmaceutical products is described. The effects of critical parameters, pH, acid molarity, and temperature, on the fluorescence intensity of PL were analyzed, and these parameters were optimized using a central composite design (CCD). The highest fluorescent intensity at excitation (λex) and emission (λem) wavelengths of 248 nm and 410 nm, respectively, was achieved using 0.01 M sulfurous acid (pH 2) at 21.6 °C. Under optimum conditions, the method was linear from 0.025-0.5 µg/mL, with a reasonably high correlation coefficient (0.9993). Furthermore, the method was very sensitive (LOQ, 0.006), accurate (RE, ≤7.06), and precise (%RSD, ≤6.51). After development and validation of the method, samples containing PL were analyzed with this method, and the obtained data were statistically compared with those obtained with a previously published reference method using a two one-sided equivalence test (TOST). According to the data, the results from the proposed and reference assays were equivalent.

Response surface methodology and process optimization of sustained release pellets using Taguchi orthogonal array design and central composite design

Singh, Gurinder; Pai, Roopa S.; Devi, V. Kusum
Fonte: Medknow Publications & Media Pvt Ltd Publicador: Medknow Publications & Media Pvt Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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65.87%
Furosemide is a powerful diuretic and antihypertensive drug which has low bioavailability due to hepatic first pass metabolism and has a short half-life of 2 hours. To overcome the above drawback, the present study was carried out to formulate and evaluate sustained release (SR) pellets of furosemide for oral administration prepared by extrusion/spheronization. Drug Coat L-100 was used within the pellet core along with microcrystalline cellulose as the diluent and concentration of selected binder was optimized to be 1.2%. The formulation was prepared with drug to polymer ratio 1:3. It was optimized using Design of Experiments by employing a 32 central composite design that was used to systematically optimize the process parameters combined with response surface methodology. Dissolution studies were carried out with USP apparatus Type I (basket type) in both simulated gastric and intestinal pH. The statistical technique, i.e., the two-tailed paired t test and one-way ANOVA of in vitro data has proposed that there was very significant (P≤0.05) difference in dissolution profile of furosemide SR pellets when compared with pure drug and commercial product. Validation of the process optimization study indicated an extremely high degree of prognostic ability. The study effectively undertook the development of optimized process parameters of pelletization of furosemide pellets with tremendous SR characteristics.

Central Composite Design for Validation of HPTLC Method for Simultaneous Estimation of Olmesartan Medoxomil, Amlodipine Besylate and Hydrochlorothiazide in Tablets

Solanki, Trupti B.; Shah, Purvi A.; Patel, Kalpana G.
Fonte: Medknow Publications & Media Pvt Ltd Publicador: Medknow Publications & Media Pvt Ltd
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
65.93%
High performance thin layer chromatographic method for simultaneous estimation of olmesartan medoxomil, amlodipine besylate and hydrochlorothiazide was developed and validated as per ICH guidelines. Moreover, robustness testing was performed applying a central composite design with k factor having 2k factorial runs, 2k axial experiments and two center points. High performance thin layer chromatographic separation was performed on aluminium plates precoated with silica gel 60F254 and toluene:chloroform:methanol:acetonitrile:formic acid (2:7:1.8:0.8:0.2% v/v) as optimized mobile phase. The detection wavelength for simultaneous estimation of three drugs was 232nm. The Rf values for olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide were 0.78, 0.20 and 0.45, respectively. Percent recoveries in terms of accuracy for the marketed formulation was found to be 101.3-104.4, 100.7-104 and 101.5-103.9 for, olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide, respectively. The pooled %relative standard deviation values for repeatability studies and intermediate precision studies was found to be less than 2% for olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide, respectively. All the three factors evaluated in the robustness testing by central composite design were found to have an insignificant effect on the retention factor. However...

A Comparison of Central Composite Design and Taguchi Method for Optimizing Fenton Process

Asghar, Anam; Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
65.85%
In the present study, a comparison of central composite design (CCD) and Taguchi method was established for Fenton oxidation. [Dye]ini, Dye : Fe+2, H2O2 : Fe+2, and pH were identified control variables while COD and decolorization efficiency were selected responses. L9 orthogonal array and face-centered CCD were used for the experimental design. Maximum 99% decolorization and 80% COD removal efficiency were obtained under optimum conditions. R squared values of 0.97 and 0.95 for CCD and Taguchi method, respectively, indicate that both models are statistically significant and are in well agreement with each other. Furthermore, Prob > F less than 0.0500 and ANOVA results indicate the good fitting of selected model with experimental results. Nevertheless, possibility of ranking of input variables in terms of percent contribution to the response value has made Taguchi method a suitable approach for scrutinizing the operating parameters. For present case, pH with percent contribution of 87.62% and 66.2% was ranked as the most contributing and significant factor. This finding of Taguchi method was also verified by 3D contour plots of CCD. Therefore, from this comparative study, it is concluded that Taguchi method with 9 experimental runs and simple interaction plots is a suitable alternative to CCD for several chemical engineering applications.

Comportamento da rebarba no fresamento de faceamento do aço inoxidável PH 13 8Mo; Behavior of the burr in face milling of PH 13 8Mo stainless steel

Silva, Luiz Carlos da
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
65.85%
Esta tese tem o objetivo de investigar a formação das rebarbas no fresamento de faceamento do aço inoxidável PH 13 8Mo. Foram utilizados insertos de metal duro intercambiáveis numa fresa de diâmetro de 63 mm. Os ensaios foram divididos em duas etapas. Na primeira etapa foram consideradas as seguintes variáveis: aplicação do fluido de corte, geometria da ferramenta, carregamento da fresa (penetração de trabalho), profundidade de corte e fresamento com as rebarbas remanescentes do corte anterior. Nesta etapa a profundidade de corte foi considerada apenas para estudar a transição da rebarba primária-secundária. Na segunda etapa dos ensaios foram aplicadas as condições de condições de corte de menor altura da rebarba, na primeira etapa. Foi utilizado um planejamento composto central onde foram variados a velocidade de corte, o avanço, a profundidade de corte, o desgaste de flanco e o ângulo de saída da peça. A medição da rebarba foi realizada em seis pontos diferentes da borda. Como sistema de medição, foi utilizado o silicone de condensação para formar a réplica da rebarba e posterior medição da sua altura no microscópio. Verificou-se que a aplicação do fluido de corte não influenciou na dimensão da rebarba...

Optimizing a culture medium for biomass and phenolic compounds production using Ganoderma lucidum; Brazilian journal of microbiology

Robles Camargo, Jorge Eliécer; Zárate Chaves, Carlos Andrés; Romero Rodríguez, María Camila; Niño Arias, Fabián Camilo; Linares Linares, Melva; Rodríguez Bocanegra, María Ximena; Gutiérrez Rojas, Ivonne
Fonte: Pontifícia Universidade Javeriana Publicador: Pontifícia Universidade Javeriana
Formato: 215-223
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Vol. 44, No. 1; The present work was aimed at optimizing a culture medium for biomass production and phenolic compounds by using Ganoderma lucidum. The culture was optimized in two stages; a Plackett- Burman design was used in the first one for identifying key components in the medium and a central composite design was used in the second one for optimizing their concentration. Both responses (biomass and phenolic compounds) were simultaneously optimized by the latter methodology regarding desirability, and the optimal concentrations obtained were 50.00 g/L sucrose, 13.29 g/L yeast extract and 2.99 g/L olive oil. Maximum biomass production identified in these optimal conditions was 9.5 g/L and that for phenolic compounds was 0.0452 g/L, this being 100% better than that obtained in the media usually used in the laboratory. Similar patterns regarding chemical characterization and biological activity towards Aspergillus sp., from both fruiting body and mycelium-derived secondary metabolites and extracts obtained in the proposed medium were observed. It was shown that such statistical methodologies are useful for optimizing fermentation and, in the specific case of G. lucidum, optimizing processes for its production and its metabolites in submerged culture as an alternative to traditional culture.

ANÁLISE EXPLORATÓRIA DAS CONCENTRAÇÕES DOS METAIS NA, CA, MG, SR E FE EM EXTRATO AQUOSO DE PETRÓLEO, DETERMINADOS POR ICP OES, APÓS OTIMIZAÇÃO EMPREGANDO PLANEJAMENTO DE EXPERIMENTOS

Souza,Murilo de O.; Rainha,Karla P.; Castro,Eustáquio Vinícius R.; Carneiro,Maria Tereza W. D.; Ferreira,Rafael de Q.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 PT
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AbstractThe purpose of this study was to evaluate the best operating conditions of ICP OES for the determination of Na, Ca, Mg, Sr and Fe in aqueous extract of crude oil obtained after hot extraction with organic solvents (ASTM D 6470-99 modified). Thus, the full factorial design and central composite design were used to optimize the best conditions for the flow of nebulization gas, the flow of auxiliary gas, and radio frequency power. After optimization of variables, a study to obtain correct classification of the 18 samples of aqueous extract of crude oils (E1 to E18) from three production and refining fields was carried out. Exploratory analysis of these extracts was performed by principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA), using the original variables as the concentration of the metals Na, Ca, Mg, Sr and Fe determined by ICP OES.

Otimização da extração sólido-líquido de antioxidantes de subprodutos florestais pelo método de superfície de resposta

Coelho, Andreia Luísa Rodrigues
Fonte: Instituto Politécnico do Porto Publicador: Instituto Politécnico do Porto
Tipo: Dissertação de Mestrado
Publicado em //2013 POR
Relevância na Pesquisa
65.93%
Portugal continental apresenta uma vasta área florestal, que representa cerca de 35,4% da ocupação total do solo, com predominância de espécies como o eucalipto (Eucalyptus globulus) e o pinheiro-bravo (Pinus pinaster). Estas espécies apresentam uma elevada importância a nível económico, designadamente devido à sua ampla utilização, nomeadamente na indústria de celulose e papel, gerando elevadas quantidades de resíduos. Este resíduo de biomassa florestal é utilizado, na sua totalidade, para a geração de energia, na forma de eletricidade ou aquecimento. No entanto, existem outras opções viáveis, a nível económico, tais como a valorização destes subprodutos como fonte de compostos polifenólicos tornando-os, assim, um produto de valor acrescentado. A extração de compostos fenólicos de subprodutos florestais, como folhas de eucalipto e agulhas de pinheiros tem vindo a aumentar devido, principalmente, à substituição de antioxidantes sintéticos, contribuindo para a valorização de subprodutos florestais. Contudo, apesar de todas as potenciais aplicações e vantagens, apenas algumas centenas de espécies aromáticas identificadas são utilizadas à escala comercial. Neste trabalho foi avaliada a capacidade antioxidante de subprodutos da floresta...

Production and optimization of a chlorophyl-free leaf protein concentrate from alfalfa (Medicago sativa) through aqueous two-phase system

Vázquez-Villegas,P.; Acuña-González,E.; Mejía-Manzano,L.A.; Rito-Palomares,M.; Aguilar,O.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 EN
Relevância na Pesquisa
65.85%
There is a growing interest in producing protein from green crops, being alfalfa (Medicago sativa) one of the more studied models. In this work we develop an aqueous two-phase systems (ATPS) process to obtain a chlorophyl-free leaf protein concentrate. A two-level factorial experimental design in order to study five factors that interferes with recovery of total protein in ATPS is performed, employing two model proteins (BSA and Lyz). The factors of polymer concentration and total protein concentration were statistically significative. From here, we applied steepest descent and central composite design (CCD) methods in order to optimize chlorophyl-free, total protein recovery from alfalfa (Medicago sativa) green tissue. An extraction of more than 809% of total protein was reached for bottom phase LPC and 51% of protein in powder from the lyophilized LPC.