Characterization of the iron bioavailability of soy root nodules and soy leghemoglobin
The development of novel iron fortification programs is an important need, because of the over 2 billion people worldwide experiencing iron deficiency and iron deficiency anemia. Soy root nodules contain a heme protein, leghemoglobin, which displays high iron bioavailability as compared to ferrous sulphate and bovine hemoglobin as determined by the rat hemoglobin repletion efficiency assay, and the in vitro caco-2 cell bioavailability assay. Leghemoglobin can be produced from soy root nodules under field conditions, as demonstrated at the Cambridge Research Station, however there were significant differences in the nodulation and leghemoglobin production characteristics of different soybean varieties, and under different agronomic treatments such as glyphosate application. Leghemoglobin can be purified from soy root nodules to greater than 90% purity by solvent extraction using sodium hydroxide, sodium chloride, or Tris-HCl, followed by ammonium sulphate fractionation, and ion exchange chromatography using DEAE Sepharose.