The Fortification of Common Salt with Ascorbic Acid and Iron

Summary. Common salt fortified with ascorbic acid or iron compounds became discoloured on storage, the reaction being accelerated by heat and humidity. Soluble iron compounds such as FeSO₄ caused discoloration more readily than insoluble compounds such as ferric orthophosphate (FePO₄). Fortification with both ascorbic acid and iron led to more rapid discoloration than fortification with either alone. Colour developed more rapidly in coarse salt than in refined commercial salt, while chemical NaCk developed a faint discoloration only under very hot and humid conditions. Discoloration was inhibited if starch was mixed with the salt: coarse salt mixed with 2.5% starch, 1.25% ascorbic acid and 0.1% iron as FePO_I retained an acceptable appearance during storage under subtropical conditions (Durban) for more than I yr. A double isotope red cell utilization method was employed to assess the absorption of iron from maize porridge and from a standard rice meal cooked with fortified salt. The absorption of both the intrinsic food iron and the iron in the fortified salt was increased threefold if the salt contained 50 mg ascorbic acid as well as FePO₄. The amount of iron absorbed was similar whether the salt contained 50 mg ascorbic acid and 4 mg iron as FePO₄ or 50 mg ascorbic acid and 4 mg iron as FeSO₄. It was concluded that crude common salt could be fortified with 0.1% iron as FePO, and 1.25% ascorbic acid and stored under all but the most extreme tropical conditions, provided that 2.5% starch was added to prevent the development of discoloration, and that such fortification would significantly improve the iron nutrition in countries where the staple food is rice or maize.