Distribution of phytic acid and phytase activity in pea seeds was analyzed and compared with those in wheat grains under identical assay conditions (55 °C, pH 5.5). Most total phytic acid content and phytase activity were found in pea cotyledons. In wheat grains, debranning resulted in a 70% reduction in phytic acid content, whereas more than 40% of the total phytase activity remained. The possibility to hydrolyze phytic acid by use of ground debranned wheat as a source of phytase in blends with pea cotyledon flour was investigated. The Michaelis-Menten parameters for each endogenous enzyme were identified and used to predict the rate of phytic acid hydrolysis. Results demonstrate a synergistic effect between the two phytase activities, enabling a 70-95% reduction of phytic acid depending on pea/wheat flour ratios in a relatively short time (4 h). This reduction appears to be able to increase zinc bioavailability but remains insufficient for iron.
Keywords: antinutritional factors; cereal; enzyme; legume; phytic acid.