Studies on the solubility of Ca, Mg, Zn, and Cu in cereal products

In vitro studies were carried out on a range of cereal products of differing phytate content in order to examine the likely release and fate of the Ca, Mg, Cu, and Zn present in cereals on passing through the stomach and small intestine. The Ca, Mg, Cu, and Zn was released by extraction with HCl (pH = 1) for 0.5 h. The addition of HCO-3 to pH 7 caused varying levels of precipitation ranging from 100% for Zn in high phytate cereals to 0% for Ca and Mg in low phytate cereals. Extracted Cu was not precipitated. The addition of the organic ligands EDTA and citric acid prevented precipitation and it is postulated that naturally occurring soluble ligands are an important controlling factor in determining the bioavailability of essential minerals.