Interactions of Fe(II), Ca(II) and Fe(III) with high dietary fibre materials: A physicochemical approach

Interactions of Fe(II), Ca(II), and Fe(III) with five natural food materials, which should be used as fibre sources in the diet, such as pomaces from the production of white wine, cider and olive oil, and lemon peel and pulp, were investigated in vitro. The extent of mineral binding by these concentrates of fibre depended both on the nature and chemical composition of the sample used and on the type of mineral element studied; however, the majority of these samples exhibited a higher capacity to bind Fe(II) than Ca(II) and Fe(III). Two graphic methods have been used to provide basic information on the mineral binding mechanisms for the interactions of these cations with the high-fibre samples: the Scatchard plot, for examining binding by complex formation, and the equation of Langmuir, to predict cation retention by physical adsorption.