Cereal Chem 64:102-105   |  VIEW ARTICLE

Interactions of Iron, Alone and in Combination with Calcium, Zinc, and Copper, with a Phytate- Rich, Fiber-Rich Fraction of Wheat Bran Under Gastrointestinal pH Conditions.

S. R. Platt and F. M. Clydesdale. Copyright 1987 by the American Association of Cereal Chemists, Inc. 

The effects of a simulated gastrointestinal pH treatment on the mineral, phytic acid, and protein solubility of a phytate-rich, fiber-rich fraction of wheat bran in the presence of Fe, alone and in combination with Ca, Zn, and Cu were determined. It was found that 98% of the phytic acid in the wheat bran fraction was soluble after a simulated gastrointestinal pH treatment. When this fraction underwent a similar treatment in the presence of 0.025 mmol of added Fe, most of the Fe was bound to the insoluble fiber fraction rather than the soluble phytic acid. Repetition of this experiment with 0.5 mmol of Ca or 0.025 mmol of Zn in the presence of 0.025 mmol of Fe indicated a decrease in the solubility of both Fe and phytic acid. However, when the experiment was repeated with 0.025 mmol of Cu in the presence of 0.025 mmol of Fe, there was no effect on Fe or phytic acid solubility but there was an increase in protein solubility; this was the only system that affected protein solubility significantly. Under the same experimental conditions with the same mineral combinations but using only Na phytate at levels equivalent to the phytic acid content of the wheat bran fraction, it was found that only Ca affected Fe and phytic acid solubility.