Iron Binding by Wheat Gluten, Soy Isolate, Zein, Albumen and Casein

The binding of iron from ferrous sulfate and ferric pyrophosphate by wheat gluten, soy isolate, zein, albumen and casein was determined in aqueous dispersions over the pH range 4–10 and at temperatures and times up to 87° C and 180 min. Under many of the experimental conditions more than 50% of the 20 mg Fe added per gram of protein became bound to the insoluble fraction of the various proteins. Lesser amounts were bound by the soluble fraction. Iron distributions between precipitated protein, soluble protein and ultrafiltrates of soluble protein were influenced by iron source, protein source, pH, temperature and time.