Cereal Chem 60:392 - 395.  |  VIEW ARTICLE
Phytic Acid and Metal Availability: A Study of Ca and Cu Binding.

T. Jacobsen and D. Slotfeldt-Ellingsen. Copyright 1983 by the American Association of Cereal Chemists, Inc. 

Two in vitro methods for the assay of the chemical form of elements were tested in solutions containing phytic acid. In the first method, we used the decrease in alpha-amylase activity to register the chelation of calcium by phytic acid. In the second method, the binding of copper by phytic acid was measured directly by electron paramagnetic resonance spectroscopy. In the calcium-alpha-amylase system, phytic acid showed an effect on the same order of magnitude as ethylenediamine-NNN'N'-tetraacetic acid. The electron paramagnetic resonance measurements showed that at stomach pH, more copper was bound to amino acids than to phytic acid.