Effect of Iron Sources and Ascorbic Acid on the Chemical Profile of Iron in a Soy Protein Isolate

Abstract

ABSTRACT The chemical changes in the iron profile of a commercial soy protein isolate resulting from ascorbic acid and iron fortification were examined. An in vitro method was devised to simulate gastrointestinal pH and an “enhancing factor” developed as a potential in vitro indicator of iron bioavailability. Ascorbic acid supplementation of soy protein produced substantial increases in soluble iron at pH 4 and 6. The solubilizing effect of ascorbic acid on iron was concentration and pH‐dependent and contingent upon the exogenous iron source present. The exogenous iron entered a different chemical pool than the endogenous iron, thus raising questions about the concept of a nonheme pool at high levels of exogenous iron.