Changes in iron, zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility

► Milling of maize grains in local traditional mills induces iron contamination/enrichment (dependent on the intensity of milling). ► Milling plus sieving allow a significant decrease of IP6/Fe and IP6/Zn molar ratios, suggesting a potential increase of mineral bioavailability. ► Extrinsic iron appears less bioaccessible than intrinsic iron. ► Total amount of bioaccessible iron is higher in samples containing extrinsic iron. ► Acidification of the food matrix lead to an increase in iron bioaccessibility.