Cereal Chem 48:377 - 384.  |  VIEW ARTICLE
Availability of Iron in Enriched Bread.

G. S. Ranhotra, F. N. Hepburn, and W. B. Bradley. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

The bioavailability of iron from sources commonly used in the enrichment of bread was determined in anemic rats fed enriched-bread diets containing 20 p.p.m. iron. On the basis of the amount of hemoglobin regenerated in 30 days, iron availability from the two reduced irons and from ferric orthophosphate was about two-thirds, and that from sodium iron pyrophosphate about one-third of that from ferrous sulfate. However, the earlier during the regeneration phase these availabilities are calculated, the more pronounced are the differences. For example, at day 15 the two reduced irons, ferric orthophosphate and sodium iron pyrophosphate were only 38, 28, and 6% as available, respectively, as ferrous sulfate. At much higher levels of iron intake (110 p.p.m.), the same iron sources were almost equally effective. Under simulated gastric conditions, the solubilities of test irons except ferrous sulfate correlated well with the results of bioassays. Tested in a separate experiment, ferric ammonium citrate was found to be somewhat better assimilated by anemic rats than ferrous sulfate on diets containing 20 p.p.m. iron. The process of baking appeared to increase iron availability somewhat.