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Search Results: 1 - 10 of 77752 matches for " José Virgílio Coelho "
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Valida??o de métodos para determina??o dos ácidos fítico e oxálico em multimistura
Nappi, Giancarlo Ubaldo;Ribeiro-Cunha, Mariem Rodrigues;Coelho, José Virgílio;Jokl, Lieselotte;
Ciência e Tecnologia de Alimentos , 2006, DOI: 10.1590/S0101-20612006000400016
Abstract: taking into account the composition of the "multimistura" distributed in belo horizonte/mg (wheat, corn meal, egg shell and cassava leave), the methods of detection and/or quantitation of phytates and oxalates were validated. the purification of phytic acid and its dephosphorylated derivatives extracted from the "multimistura" using a strong anionic exchange column presented low values of recovery (49%) at low concentrations of the added phytate, when related to the higher ones (101%), which suggests interference of minerals present in high levels, mainly calcium. from the methods evaluated for the determination of oxalic acid, the ionic exclusion chromatography was the one that presented the best results, with good recoveries at the highest addition levels (88%); presenting, however, decreased recovery in the lower levels of addition (61%). the levels of phytic acid in the samples varied from 1.61 g/100 g to 2.25 g/100 g and for the oxalic acid, from 0.044 g/100 g to 0.057 g/100 g. the validation criteria for the analytical methods by high performance liquid chromatography were considered satisfactory for selectivity and specificity, linearity, repetitivity and limits of detection and quantitation. however, the recovery was not satisfactory since the obtained percentages were lower than the expected one, taking into account the quantities added to the samples.
Imobiliza o da pancreatina em carv o ativado e em alumina para o preparo de hidrolisados de soro de leite = Immobilization of pancreatin in activated carbon and in alumina for preparing whey hydrolysates
Viviane Dias Medeiros Silva,Letícia Missagia De Marco,Fernanda Meneghello Delvivo,José Virgílio Coelho
Acta Scientiarum : Health Sciences , 2005,
Abstract: Tendo como objetivo a redu o de custos do processo de fabrica o dehidrolisados protéicos, estudou-se neste trabalho a imobiliza o da pancreatina, por adsor o, em carv o ativado e em alumina. Para isso, foram testadas diferentes condi es de imobiliza o (30, 60 e 90min a 25°C, e 12h a 5°C). Para verificar a taxa de imobiliza o, determinou-se indiretamente a enzima n o adsorvida nos suportes. Ao se utilizar o carv o ativado, n o foi observada diferen a significativa entre as condi es testadas, tendo-se obtido 100% de imobiliza o enzimática. Para a alumina, a melhor condi o foi a de 90min, na qual se obteve 37% de imobiliza o. A medida do grau de exposi o da fenilalanina, pela espectrofotometria derivada segunda, foi empregada para a determina o da estabilidade operacional da enzima, tendo sido mostrado que a imobiliza o em carv o ativado e emalumina permitiu a reutiliza o da pancreatina por até 5 vezes e 2 vezes, respectivamente. Immobilization of pancreatin in activated carbon and in alumina was studied for producing protein hydrolysates, in order to reduce the process costs. Different immobilization conditions were tested (30, 60 and 90min at 25°C, and 12h at 5°C). For estimating the immobilization rate the amount of the non-adsorbed enzyme on the supports was indirectly determined. When activated carbon was used, no significant difference was observed among the tested conditions, obtaining 100% of enzymatic immobilization. In case of alumina, the best condition showed to be the 90min treatment which produced 37% of immobilization. The evaluation of the degree of exposition ofphenylalanine, by second derivative spectrophotometry, was used for the determination of the enzyme operational stability, and showed that the immobilization in activated carbon and in alumina allowed the reusability of the pancreatin for 5 times and 2 times,respectively.
PROPRIEDADES EMULSIFICANTES E SOLUBILIDADE DA CASEíNA BOVINA E DE SEUS HIDROLISADOS TRíPTICOS: 1. EFEITO DO PH E DO TEMPO DE HIDRóLISE
DUARTE ?ngela Jardim,CARREIRA Raquel Linhares,JUNQUEIRA Roberto Gon?alves,COELHO José Virgílio
Ciência e Tecnologia de Alimentos , 1998,
Abstract: Visando a aplica o industrial da caseína e de seus hidrolisados trípticos, foram estudados os efeitos da varia o do pH e do tempo de hidrólise sobre suas características de solubilidade e propriedades emulsificantes. Testou-se os valores de pH de 3,0; 4,0; 5,0; 6,0; 7,0 e 8,0 e os tempos de hidrólise: 5, 10 15, 30 e 60min. Foram medidos a solubilidade, a capacidade emulsificante, o índice de atividade emulsificante, a estabilidade da emuls o, e calculdado o tamanho dos glóbulos de gordura. Os resultados obtidos para a caseína nativa indicaram que os melhores valores para estas propriedades funcionais foram encontrados em pH acima de 5,0. A hidrólise tríptica da caseína foi benéfica para sua solubilidade e capacidade emulsificante e prejudicou sua estabilidade, em todos os valores de pH e tempos de hidrólise, exceto no pH 5,0 com 5 min de rea o. Por outro lado, este tratamento enzimático contribuiu para melhorar o índice de atividade emulsificante da caseína, entre valores de pH 3,0 e 5,0 e após 10 min de rea o.
PROPRIEDADES EMULSIONANTES E SOLUBILIDADE DA CASEíNA BOVINA: 2. EFEITO DA ADI O DE NaCl
DUARTE ?ngela Jardim,CARREIRA Raquel Linhares,JUNQUEIRA Roberto Gon?alves,COELHO José Virgílio
Ciência e Tecnologia de Alimentos , 1998,
Abstract: O efeito da adi o de NaCl sobre algumas propriedades funcionais da caseína e de seus hidrolisados trípticos, foi estudado em dois valores de pH (4,0 e 5,0). Para tal, foi adicionado um teor de 0,02M do sal às solu es-tamp o empregadas no preparo das amostras. Foram determinadas a solubilidade protéica, a capacidade emulsificante (EC), o índice de atividade emulsificante (EAI) e a estabilidade das emuls es (ES), e o raio médio dos glóbulos de gordura (R) foi calculado. Os resultados obtidos indicaram que, nos dois valores de pH estudados, a adi o de NaCl levou a um aumento significativo da solubilidade e da EC da caseína e de todos os hidrolisados trípticos. Por outro lado, diminuiu os valores de EAI da caseína e elevou os dos hidrolisados, tendo sido observado o oposto para o tamanho dos glóbulos de gordura. Com rela o à ES, a da caseína apresentou ligeiro aumento no pH 5,0, enquanto que apenas alguns hidrolisados trípticos tiveram a sua ES elevada em pH 4,0 ou 5,0.
PROPRIEDADES EMULSIFICANTES E SOLUBILIDADE DA CASEíNA BOVINA E DE SEUS HIDROLISADOS TRíPTICOS: 1. EFEITO DO PH E DO TEMPO DE HIDRóLISE
DUARTE, ?ngela Jardim;CARREIRA, Raquel Linhares;JUNQUEIRA, Roberto Gon?alves;COELHO, José Virgílio;SILVESTRE, Marialice Pinto Coelho;
Ciência e Tecnologia de Alimentos , 1998, DOI: 10.1590/S0101-20611998000300008
Abstract: the effects of ph and hydrolysis time on the solubility and emulsifying properties were studied, in view of the industrial application of casein and its tryptic hydrolyzates. it has been tested the ph values of 3,0; 4,0; 5,0; 6,0; 7,0 and 8,0 and the reaction times: 5, 10, 15, 30 and 60 min. it has been evaluated the solubility, the emulsifying capacity, the emulsifying activity index and the emulsion stability. the results show that the best values for the functional properties of native casein were achieved at ph above 5,0. the tryptic hydrolysis of casein favored the solubility and emulsifying capacity but reduced the emulsion stability, at all ph and hydrolysis times, except in ph 5,0 with 5min of reaction. otherwise, this enzymatic treatment improved the emulsifying activity index of casein only between ph 3,0- 5,0, after 10 min of reaction.
PROPRIEDADES EMULSIONANTES E SOLUBILIDADE DA CASEíNA BOVINA: 2. EFEITO DA ADI??O DE NaCl
DUARTE, ?ngela Jardim;CARREIRA, Raquel Linhares;JUNQUEIRA, Roberto Gon?alves;COELHO, José Virgílio;SILVESTRE, Marialice Pinto Coelho;
Ciência e Tecnologia de Alimentos , 1998, DOI: 10.1590/S0101-20611998000300009
Abstract: the effect of the nacl addition on the emulsifying properties of casein and tryptic casein hydrolysates was studied in two ph values (4,0 e 5,0). a 0.02 m concentration of salt was added to the buffer solutions used for preparing the samples. the protein solubility, the emulsifying capacity (ec), the emulsifying activity index (eai) and the emulsion stability (es) were determined. the mean radius (r) of fat droplets was also calculated. the results showed that the addition of nacl increased the solubility and the ec of casein and casein hydrolysates, in both ph values. however, this salt addition reduced the eai of casein and increased that of the hydrolysates.the opposite was observed relating to the r of fat droplets. regarding the es, that of casein presented little increase in ph 5.0, and the same result was obtained for only some hydrolysates in ph 5.0 or 4.0.
Extra??o química e enzimática das proteínas do fubá de milho
Capobiango, Michely;Vieira, Claudia Regina;Silva, Ana Luiza Santiago e;Coelho, José Virgílio;Segall, Sérgio Duarte;Silvestre, Marialice Pinto Coelho;
Ciência e Tecnologia de Alimentos , 2006, DOI: 10.1590/S0101-20612006000400027
Abstract: different chemical methods and an enzymatic one were tested for protein extraction from brazilian corn flour. the protein extraction yield was calculated using the values of protein and solid contents of the residues. for the chemical extraction, an alkaline solution, separately or in association with ethanol, was used as a solvent. the sequential alkaline-alcoholic method was the most efficient, having reached a yield of 88.2%. however, the alkaline method presents the advantage of not using ethanol, reducing the risks for health, as well as decreasing the costs of the process. for the enzymatic extraction, a protease of bacillus liccheniformis was used. the time and the temperature used in this method influenced the extraction yield. the best results were obtained for 5, 15 and 24 hours at 55°c, and the most advantageous condition from the economical point of view, was that one obtained for 5 hours at 55°c, having reached a yield of 83.8%.
A??o da pancreatina na obten??o de hidrolisados protéicos de soro de leite com elevado teor de oligopeptídeos
Biasutti, Eliza Augusta Rolim;Afonso, Wendel de Oliveira;Lopes Junior, Carlos de Oliveira;Coelho, José Virgílio;Silva, Viviane Dias Medeiros;Silvestre, Marialice Pinto Coelho;
Revista Brasileira de Ciências Farmacêuticas , 2008, DOI: 10.1590/S1516-93322008000100007
Abstract: several enzymatic hydrolysates of whey were prepared with the objective of increasing the oligopeptide content and reducing the cost of large scale production. pancreatin was used and some hydrolytic parameters such as reaction time (5, 10 and 15h), enzyme:substrate ratio (e:s) (1:100, 2:100 and 4:100) and substrate concentration (10 and 15%) were tested. the hydrolysates were fractionated by size-exclusion-hplc and the rapid corrected fraction area method was used for quantifying the chromatographic fractions. the beneficial effect on the peptide profile was observed in several cases, and it was mainly associated with higher oligopeptide (49%) and lower amino acid (22%) contents, which were obtained for a substrate concentration of 10%, e:s ratio of 4:100 and reaction time of 10h.
Computational Tools to Support Ethanol Pipeline Network Design Decisions  [PDF]
Gustavo Dias da Silva, Virgílio José Martins Ferreira Filho, Laura Bahiense
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.31001
Abstract:

This paper considers the pipeline network design problem (PND) in ethanol transportation, with a view to providing robust and efficient computational tools to assist decision makers in evaluating the technical and economic feasibility of ethanol pipeline network designs. Such tools must be able to address major design decisions and technical characteristics, and estimate network construction and operation costs to any time horizon. The specific context in which the study was conducted was the ethanol industry in Sao Paulo. Five instances were constructed using pseudo-real data to test the methodologies developed.

Sistemas computacionais para o gerenciamento estratégico da logística
Ferreira Filho Virgílio José Martins
Pesquisa Operacional , 2000,
Abstract:
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