Partial characterization and inactivation of peroxidases and polyphenol-oxidases of umbu-cajá (Spondias spp.)
A crude extract of Spondias spp. was evaluated for the influence of pH and temperature on the activity and stability of its peroxidases and polyphenol-oxidases. In order to evaluate the conditions for the inactivation of the enzymes by heat treatment and by addition of a reducing agent, a factorial...
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Published in | Ciência e tecnologia de alimentos Vol. 30; no. 3; pp. 790 - 796 |
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Main Authors | , |
Format | Journal Article |
Language | English Portuguese |
Published |
Sociedade Brasileira de Ciência e Tecnologia de Alimentos
01.09.2010
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Subjects | |
Online Access | Get full text |
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Summary: | A crude extract of Spondias spp. was evaluated for the influence of pH and temperature on the activity and stability of its peroxidases and polyphenol-oxidases. In order to evaluate the conditions for the inactivation of the enzymes by heat treatment and by addition of a reducing agent, a factorial experimental design (n = 3) was employed using the Statistica (6.0) software package for data analysis. The optimal conditions found for peroxidases were: pH = 5.0 and temperature = 40 ºC, and for polyphenol-oxidases they were pH = 7.0 and temperature = 40 ºC. The peroxidases and polyphenol-oxidases were stable at all pH values tested (3.0 - 10.0) and maintained more than 60% of their activity at temperatures above 30 and 40 ºC, respectively. To achieve the total inactivation of these enzymes, two alternatives can be suggested: incubation at 92 ºC for 3.15 minutes with 200 mg.L-1 of ascorbic acid or incubation at 96 ºC for 2.80 minutes with 100 mg.L-1 of ascorbic acid.
O extrato bruto de umbu-cajá foi avaliado quanto à influência do pH e da temperatura na atividade e na estabilidade de peroxidases e polifenol-oxidases nativas. Para avaliação das condições de inativação das enzimas por tratamento térmico e por adição de agente redutor (ácido ascórbico), foi realizado um experimento fatorial (n = 3) com aplicação do software Statistica (6.0) para elaboração da planilha de ensaios e das superfícies de resposta. Para as peroxidases, foram encontrados os seguintes parâmetros ótimos: pH = 5,0 e temperatura = 40 ºC. E para polifenol-oxidases: pH = 7,0 e temperatura = 40 ºC. Ambas as enzimas foram estáveis em toda a faixa de pH testada (3,0 - 10,0), peroxidases e polifenol-oxidases mantiveram acima de 60% de sua atividade em temperaturas acima de 30 e 40 ºC, respectivamente. Para inativação total das enzimas em teste, duas alternativas foram sugeridas: 200 mg.L-1 de ácido ascórbico, 92 ºC/3,15 minutos ou 100 mg.L-1 de ácido ascórbico, 96 ºC/2,80 minutos. |
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Bibliography: | http://www.scielo.br/scielo.php?pid=S0101-20612010000300035&script=sci_abstract&tlng=pt |
ISSN: | 0101-2061 1678-457X 1678-457X |
DOI: | 10.1590/S0101-20612010000300035 |