Kinetic study of enzymatic α-galactoside hydrolysis in cowpea seeds

Fanny Coffigniez; Aurélien Briffaz; Christian Mestres; Julien Ricci; Pascaline Alter; Noel Durand; Philippe Bohuon

doi:10.1016/j.foodres.2018.07.030

Kinetic study of enzymatic α-galactoside hydrolysis in cowpea seeds

Food Res Int. 2018 Nov:113:443-451. doi: 10.1016/j.foodres.2018.07.030. Epub 2018 Jul 27.

Authors

Fanny Coffigniez¹, Aurélien Briffaz², Christian Mestres¹, Julien Ricci¹, Pascaline Alter¹, Noel Durand¹, Philippe Bohuon³

Affiliations

¹ UMR Qualisud, CIRAD, Univ Montpellier, TA B-95/16, 73 rue J-F. Breton, F- 34398 Montpellier cedex 5, France.
² UMR Qualisud, CIRAD, Univ Montpellier, TA B-95/16, 73 rue J-F. Breton, F- 34398 Montpellier cedex 5, France. Electronic address: aurelien.briffaz@cirad.fr.
³ UMR QualiSud Food Process Engineering Research Unit, Montpellier SupAgro, Univ Montpellier, 1101 av. Agropolis, B.P. 5098, F-34093 Montpellier cedex 5, France.

PMID: 30195540
DOI: 10.1016/j.foodres.2018.07.030

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 ± 3 and 103 ± 9 kJ.mol^-1, respectively. The strongest inhibitor was galactose with an inhibition constant K_I 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 K_m 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.

Keywords: Alpha-galactosidase; Cooking; Hydrolysis; Inhibitor; Legume; Michaelis–Menten; Soaking.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cooking
Galactosides* / chemistry
Galactosides* / isolation & purification
Galactosides* / metabolism
Hydrogen-Ion Concentration
Hydrolysis
Kinetics
Particle Size
Plant Proteins* / chemistry
Plant Proteins* / isolation & purification
Plant Proteins* / metabolism
Seeds / enzymology*
Temperature
Vigna / enzymology*

Substances

Galactosides
Plant Proteins