Fortification of sorghum (Sorghum vulgare) and pearl millet (Pennisetum glaucum) flour with zinc

Deficiency of zinc is believed to be as widespread as that of iron, with equally serious consequences. Fortification of staple foods with this mineral is a cost-effective method that can be used to combat this deficiency. In the present study, flours of pearl millet and sorghum were evaluated as vehicles for fortification with zinc. Zinc stearate was used as the fortificant, and added at a level that provided 5 mg Zn/100 g flour. The metal chelator EDTA was used as a co-fortificant, the molar ratio of exogenous Zn:EDTA being 1:1. Bioaccessibility of zinc from the fortified flours, both raw and cooked, was determined by an in vitro simulated gastrointestinal digestion procedure. The results of the study revealed that there were differences among these two flours with respect to the feasibility of fortification with zinc. Although fortified pearl millet flour provided a higher amount of bioaccessible zinc, this was attributable to the presence of EDTA, rather than to the fortified zinc. The benefit of fortification with zinc was more evident in sorghum flour, compared to that in pearl millet flour, the increase in bioaccessible zinc content being more than 1.5 times higher as a result of fortification. Fortified sorghum and pearl millet flours were stable during storage for a period of up to 60 days. Thus, millet flours seem to be satisfactory candidates for fortification with zinc, and can be exploited to address zinc deficiency.