The effect of multi-mineral mix (Fe, Zn, Ca and Cu) on magnesium binding to starchy legumes under simulated gastrointestinal conditions

The present in vitro study on starchy legumes and their Mg bioavailability, covers the factors: cooking, dietary fibre, phytic acid and the competitive binding of other minerals. Mg-binding capacity of food legumes (butter beans, broad beans and lentils) in the raw, cooked and fibre-rich fraction (FRF) forms with Mg addition alone and with Ca, Fe, Zn and Cu (at concentrations based on the recommended daily allowance) was investigated in conditions simulating the small intestine. The three legumes in the raw and cooked forms showed more significant (P<0.01) Mg-binding when Mg was added with Ca, Fe, Zn and Cu than with Mg addition alone. The FRFs were found to bind significantly (P<0.01) more Mg than the raw and cooked forms. Cooking significantly decreased (P<0.01) the Mg-binding capacity of raw butter beans, broad beans and lentils at separate Mg addition or with Ca, Fe, Zn and Cu.