Cereal Chem 60:121 - 123. | VIEW
Improved Ion-Exchange Phytate Method.
R. Ellis and E. R. Morris. Copyright 1983 by the American Association of Cereal Chemists, Inc.
A modified ion-exchange method was developed for phytate analysis. Data from the modified method indicate that the apparent phytate levels previously determined in some materials by ion-exchange methods were lower than actual levels because some phytate in the acid extract is bound to metal, to protein, or to both. The effect of apparent binding was eliminated when ethylenediamine tetraacetate was added to the acid extract and the pH adjusted to 6. The modified procedure recovers phytate quantitatively from wheat products, human composite diets, and fecal samples. In contrast to data from other ion-exchange methods, data from the modified ion-exchange method agreed closely with that from the iron-precipitation method when the phytate content of the product was above 0.2%. The iron-precipitation procedure is not sensitive to low concentrations of phytate. Concentration is not a factor with the modified ion-exchange procedure.