Cereal Chem 59:216 - 221.  |  VIEW ARTICLE
Phytic Acid. III. Two Barriers to the Loss of Phytate During Breadmaking.

U. Tangkongchitr, P. A. Seib, and R. C. Hoseney. Copyright 1982 by the American Association of Cereal Chemists, Inc. 

Phytate phosphorus (Pp) decreased linearly with time in a 2% yeasted, whole wheat dough at pH 4 during 0- 6 hr of fermentation. After 6 hr, 70% Pp was lost. During fermentation at pH 6, Pp decreased linearly for 3 hr; then its rate of loss declined. During the first 3-hr fermentation period at pH 6, 34% Pp was lost, but only 9% more was lost after an additional 3 hr. In a fermenting dough, Pp was lost almost twice as rapidly at pH 5 as at pH 4 or 6. The solubility of sodium phytate in aqueous solution containing magnesium, calcium, iron, and zinc ions depended strongly on pH; 75% of phytate was insoluble between pH 6 and 7, whereas 15% was insoluble at pH 5. The barrier to destroying phytate in whole wheat dough above pH 6 is the insolubility of its magnesium salt, whereas at pH 5 the limiting factor appears to be the level of phytase.