Cereal Chem 44:346 - 351.  |  VIEW ARTICLE
The State of Iron in Flour, Dough, and Bread.

J. Leichter and M. A. Joslyn. Copyright 1967 by the American Association of Cereal Chemists, Inc. 

The available (extractable) iron in three different types of bread was determined chemically by the modified 2,2-dipyridyl method. In the breads examined, the total and the extractable iron values were identical. The iron contents of white enriched bread, rye bread, and French enriched bread were 33, 21, and 35 p.p.m., respectively (moisture-free basis). Changes in the available iron from flour to dough to bread were examined. It was found that the available iron in flour and in dough is approximately 80% of the total iron, which is approximately 20% lower than the available iron value in bread. No differences in results were noted whether the bread was made from enriched or unenriched flour. Aqueous extraction of bread does not liberate bread iron into the solution. When a reducing agent (sodium hydrosulfite) is added, all of the iron found in the bread is released into the solution. Further investigations of iron-binding capacity have shown that more of the added ferric than ferrous iron forms insoluble complexes with bread. The iron present in bread was found largely in the ferric state.