Search

The adsorption of several iron compounds by unmodified and modified tapioca, corn and waxy maize starch was studied using transmission electron microscopy and atomic absorption spectrophotometry. Starch was incubated in an iron-containing solution. After centrifugation the amount of iron remaining in solution was compared to the original concentration to determine the quantity bound by the starch. Only iron in the form of colloidal ferric chloride showed significant binding. Long, cigar shaped structures, probably β-ferric oxyhydroxide crystals, were seen embedded in the surface of the granule. It is postulated that the oxygen and hydroxide groups surrounding the iron are responsible for binding to the carbohydrate. The study of the interaction of starch and metal compounds may lead to greater insight into methods of fortifying food products.