Feasibility and optimization study of using cold-forming extrusion process for agglomerating and microencapsulating ferrous fumarate for salt double fortification with iodine and iron

A microencapsulation-based technology platform has been developed for salt double fortification with iron and iodine, aiming to address two globally prevalent micronutrient deficiencies simultaneously. Specifically, ferrous fumarate was microencapsulated into a form of salt grain-sized premix, and then added into iodised salt. The earlier process involved fluidised-bed agglomeration followed by lipid coating. To improve physico-chemical properties of the iron premix, the use of cold-forming extrusion for agglomerating and microencapsulating ferrous fumarate was investigated and optimized in this study, leading to optimal formulations and operation parameters. Grain flours were suitable for forming an extrudable dough incorporating high percentages of ferrous fumarate. All extruded iron particles, regardless of binders used, were rich in iron and had excellent iron in vitro digestibility. The extruded iron particles formed the basis of the final, microencapsulated iron premixes with desired particle size (300-700 µm), and other physical, chemical, nutritional, and organoleptic properties suitable for salt fortification.