Development and pilot scale demonstration of encapsulated ferric pyrophosphate premixes for double and multiple fortified salt with vitamins B9,B12, iodine and zinc

Ferric pyrophosphate (FePP) was evaluated as an iron fortificant alternative to ferrous fumarate due to its favorable sensory properties in fortified foods. However, its low bioavailability limits nutritional efficacy. To enhance absorption, previously developed adjuncts—disodium ethylenediaminetetraacetate dihydrate, citric acid, trisodium citrate, and sodium pyrophosphate—were incorporated, demonstrating increased FePP bioavailability in prior studies. In previous double-fortified salt (DFS) formulations, uncoated FePP in the presence of iodide caused rapid iodine loss, compromising product stability. This challenge prompted the development of a protective coating system designed to preserve iodine while maintaining iron bioavailability. Extrusion of FePP with adjuncts produced unacceptable colour changes, necessitating colour masking, similarly to approaches used with ferrous fumarate in DFS. The coating system was successfully tested on pilot scale for multiple fortified salt (MFS) formulations containing iron (FePP with adjuncts or FeFum), iodine, zinc, vitamins B9 and B12. After six months of storage under elevated temperature and humidity, both DFS and MFS remained stable, confirming that soy stearin provided an effective moisture barrier and prevented significant iodine loss under typical use conditions. Zinc oxide proved superior to zinc sulfate in MFS in terms of iodine stability. Due to FePP's lower iron content and the requirement for adjuncts, higher premix quantities were necessary, increasing premix addition level and cost. However, the estimated costs of $0.86–1.05 USD per person per year, or $0.23–0.29 USD/kg of salt is still acceptable. FePP is a viable iron fortificant for salt, yielding stable, visually acceptable, and nutritionally effective DFS and MFS formulations.