Phytate content and phytate degradation by endogenous phytase in pea (Pisum sativum)

In order to rapidly reduce the content of inositol tri-hexaphosphates in pe a flour by action of the endogenous phytase, raw materials as well as incub ation conditions have been evaluated. The phytate (inositol hexaphosphate) content was analysed in 27 pea varieties; the influence of storage time and the difference in phytate content between the germ and the cotyledon were determined. Furthermore, degradation of inositol phosphates by the endogeno us phytase enzyme was studied in pea flour, germ and cotyledon. To find the maximum phytate degradation, the effects of temperature and pH during pea flour incubation were investigated. The most efficient phytate degradation in pea flour incubation was achieved at pH 7.5 and 45 degreesC. At this con dition an almost complete degradation of phytate and a 66% reduction in the sum of inositol hexa-, penta-, tetra- and triphosphates were reached in 10 h. The storage time of pea seeds or removal of the germ did not have a majo r effect on the phytate content. Since several inositol pentaphosphate isom ers were produced during phytate degradation, it can be concluded that peas contain several phytate-degrading enzymes, or one phytate-degrading enzyme with unspecific initial hydrolysation pattern. (C) 2001 Society of Chemica l Industry.