Titanium dioxide replacement with inorganic alternatives for color-masking of ferrous fumarate in double fortified salt

Abstract

Background

Titanium dioxide (TiO₂) has been widely used in food products, including gums, candies and in fortified salt as a white coloring agent of iron premixes. TiO₂ (E171) was banned by the European Food Safety Authority in 2021, with potential carcinogenicity concerns. This study assesses the feasibility of using inorganic alternatives to replace TiO₂ in ferrous fumarate-based iron premixes for salt fortification for treatment of iron and iodine deficiencies.

Results

Varying levels of alternatives were utilized: calcium carbonate, magnesium carbonate, zinc oxide, calcium sulfate, and commercial formulations Opadry®, and Nutrafinish®. Adhesives included HPMC and gum Arabic with soy stearin as an overcoat moisture barrier. Preliminary results for MgCO₃ premixes had poor adhesion, leading to exposed iron, which will be addressed in further studies. ZnO, Opadry, CaCO₃ and CaSO₄ premixes resembled TiO₂ premixes in terms of coverage and color, especially CaSO₄, attributed to calcium sulfate's small particle size resulting in high surface area for coverage. Premixes stored in iodized salt at 25, 35, 45°C and elevated humidity, for 9-month stability studies retained over 70% iodine, confirming successful encapsulation.

Conclusions

CaSO₄, CaCO₃ and ZnO premixes were successful in terms of appearance and stability of fortificants over 9-month storage. The levels of calcium in fortified salt were lower than that which would impede iron absorption. Therefore, these calcium and zinc alternatives would be suitable alternatives to titanium dioxide premix for use in fortified salts. Premixes will be scaled-up for cost-effective salt fortification to address micronutrient deficiencies in low middle income countries.