Pilot plant batches of liquid soy isolate infant formula products were prepared without added iron and with various added iron salts by standard commercial techniques. Three of the iron salts also were added without processing to lyophilized product made without added iron. Measured amounts of the lyophilized products were fed to anemic rats; hemoglobin responses were used to evaluate iron availability. Processing had little effect on the availability of ferrous sulfate, whereas it increased the relative availability of the iron of ferric pyrophosphate from 39 to 93, expressed as a percentage of reagent grade ferrous sulfate, and of sodium iron pyrophosphate from 15 to 66. The iron in a production batch of a commercially available soy isolate infant formula containing sodium iron pyrophosphate as the added iron salt had a relative availability of 77. The results indicate that the availability of iron added to foods should be determined only after normal processing.

No abstract

No abstract