Production of Iron Premix for the Fortification of Table Salt

Abstract

Abstract The feasibility of using fluidized bed technology for the production of an iron premix of ferrous fumarate encapsulated with soy stearine for iron fortification of table salt has been successfully demonstrated. Ferrous fumarate was selected as source of iron, in preference to ferrous sulphate heptahydrate, ferric sodium EDTA and reduced elemental iron, for its bioavailability, bland taste, stability and high iron content. Potassium iodate was used as iodine source. Fluid-bed processors of 7, 200 and 500 kg capacity were used to granulate ferrous fumarate with a solution containing, hydroxypropylmethylcellulose, sodium hexametaphosphate and titanium dioxide for binding, stabilization and colour masking, respectively. Encapsulation of granulated ferrous fumarate was achieved by top-spraying hot soy stearine containing more titanium dioxide at 98ºC on the fluidized bed. The premix contained 46.4 wt. % of ferrous fumarate. Double Fortified Salt (DFS), made by dry blending 1 part of iron premix and 150 parts of already iodized salt, contained 1000 ppm of iron and 50 ppm of iodine. Less than 10% of the iron in the premix, with a bulk density of 0.78 g/cc, dissolved in HCl at pH of 4.0 indicating good coating integrity. Particle size distribution of iron premix was consistently centred on 300 µm with more than 90% of the particles in the size range of 150 to 710 µm, similar to that of free flowing refined salt.