Binding of mineral elements by dietary fibre components in cereals-In vitro (III)

The ability of soluble fibre fractions isolated from three different cereals (barley flour, whole grain rye flour and oat bran) to bind copper(II), cadmium(II) and zinc(II) ions has been studied using a potentiometric method. Considerable association was found between all fibre fractions and metals investigated. The ability of the metal ions to form complexes was found to be in the order Cu(II) > Zn(II) ≈ Cd(II) for all cereal fibres. The order of interaction for the fibres with metal ions was barley > oats ≈ rye. Between pH 3·5 and 5 phytic acid was an important complexing agent, especially for oats. No metal complexing ability was found for pure β-glucans, isolated from barley.