Inositol phosphate degradation by the action of phytase enzyme in legume seeds

The kinetics of mositol phosphate degradation during the action of naturally occurring endogenous phytase for up to 90 min in pea and lentil flours has been studied, and compared with the addition of commercial phytase enzyme. In raw lentils IP6, IP5, IP4 and IP3 were present, whilst in peas only the presence of IP6 and IP5 was observed. Endogenous phytases were activated when legume flour was suspended in acidified water at pH 5.5 and 37 degreesC, and significant differences between lentils and peas were found. IP6 suffered a sharp reduction in lentils and peas (81-91 and 73-93%, respectively), this reduction being slightly more pronounced after the addition of commercial phytase. The,content of IP5 decreased in lentils (48-69%), and increased in peas, except when commercial phytase acted for the first 30 min, after which a reduction was found (23%). The content of IP4 generally decreased in lentils, except when endogenous phytase acted for 30 min when an increase was observed. However, in peas, IP4 appeared in high concentrations up to 60 min by the action of both endogenous and exogenous phytases. The content of IP3, on the other hand, did not change greatly in lentils. In peas it was not detected after the action of endogenous phytase enzyme and it appeared in a large amount after the action of commercial phytase. In order to obtain legume flour with low IP6 and IP5 contents and notable IP4 and IP3 contents, the action of naturally endogenous phytase for 30 min in lentils is recommendable, as well as the addition of commercial phytase enzyme for 60 min in peas. (C) 2002 Elsevier Science Ltd. All rights reserved.