Kinetics of soluble carbohydrates by action of endo/exo α-galactosidase enzyme in lentils and peas

The kinetics of soluble sugars (available sugars and α-galactosides) during the action of naturally occurring endogenous α-galactosidase for up to 90 min in lentil and pea flours has been studied, and it has been compared with the addition of commercial α-galactosidase enzyme. Raw lentil and pea seeds presented sucrose, raffinose, stachyose and verbascose, whilst ciceritol was only present in lentils. No monosaccharides were detected in either of the raw seeds. After the action of endogenous α-galactosidase or by the addition of commercial α-galactosidase, fructose, glucose and galactose were detected in legume flours. The action of endogenous α-galactosidase for 15-90 min in lentils or peas produced a reduction of sucrose (77% and 73-81%), raffinose (73-77% and 59-79%), stachyose (76-81% and 77%) and verbascose (100% and 70-83%), respectively. When commercial α-galactosidase was added to lentils or peas the observed decreases were in sucrose (77-73% and 62-64%), raffinose (61-68% and 41-48%), stachyose (80-85% and 67-91%) and verbacose (100% and 77-95%) respectively. The action of endogenous α-galactosidase or the addition of commercial α-galactosidase could produce lentil or pea flours with very small flatulence factors and, therefore, with a high functionality. According to these data, the optimal conditions to obtain lentil and pea flour with the lowest α-galactoside content were the addition of commercial α-galactosidase at 37°C in buffer pH 5.5 for 90 min. In these conditions the largest contents in fructose, glucose, galactose and sucrose were obtained.This work was supported by the project CICYT (ALI 97–0636) and is part of Ph D. of R. Doblado.Peer Reviewe