Kinetic study of enzymatic α-galactoside hydrolysis in cowpea seeds.
Food Res Int
; 113: 443-451, 2018 11.
Article
em En
| MEDLINE
| ID: mdl-30195540
ABSTRACT
The endogenous alpha-galactosidase activity of cowpea seeds was characterized and modelled assuming Michaelian behavior. The aim is to use the resulting knowledge to optimize alpha-galactoside degradation during the soaking-cooking process. In this study, the alpha-galactosidase enzyme from Wankoun cowpea was extracted and its enzymatic activity was analyzed as a function of temperature, pH and the presence of some inhibitors. Enzymatic activity was optimal around 35⯰C and a pH of 5.8. Activation and inactivation energy was evaluated at 50⯱â¯3 and 103⯱â¯9â¯kJ.mol-1, respectively. The strongest inhibitor was galactose with an inhibition constant KI of 0.28⯱â¯0.03â¯mM. Incubation of the enzyme extract with alpha-galactosides revealed a 10-h lag phase in the early stages that could be due to low pH, the action of inhibitors including galactose and the biosynthesis of alpha-galactosides. After the lag phase, the degradation of each alpha-galactoside occurred without the appearance of any intermediary product. The degradation of alpha-galactosides was observed with a Km of 1.7⯱â¯0.3â¯mM for raffinose; 3.6⯱â¯0.6â¯mM for stachyose and 15.9⯱â¯0.1â¯mM for verbascose. A long soaking step around 35⯰C is suggested to maximize the alpha-galactosides enzymatic degradation.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Sementes
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Vigna
/
Galactosídeos
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article