Kinetic study of enzymatic α-galactoside hydrolysis in cowpea seeds
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 ± 3 and 103 ± 9 kJ.mol−1, respectively. The strongest inhibitor was galactose with an inhibition constant KI of 0.28 ± 0.03 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 ± 0.3 mM for raffinose; 3.6 ± 0.6 mM for stachyose and 15.9 ± 0.1 mM for verbascose. A long soaking step around 35 °C is suggested to maximize the alpha-galactosides enzymatic degradation.
| Main Authors: | , , , , , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | F60 - Physiologie et biochimie végétale, Q04 - Composition des produits alimentaires, niébé, enzyme, biosynthèse, cuisson, http://aims.fao.org/aos/agrovoc/c_1938, http://aims.fao.org/aos/agrovoc/c_2603, http://aims.fao.org/aos/agrovoc/c_928, http://aims.fao.org/aos/agrovoc/c_1851, |
| Online Access: | http://agritrop.cirad.fr/589235/ http://agritrop.cirad.fr/589235/1/1-s2.0-S0963996918305684-main.pdf |
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