Edible matrices developed by ionic gelation improve the acceptability of iron sources for mammals: model weaned pigs

The objective of this study was to evaluate pigs' preference for feed fortified with heme iron (HI) and non-heme iron (NHI), to develop edible matrices (EMs) as delivery vehicles for both iron sources, and to assess pigs' feeding behavior towards these matrices. Pigs showed equal preference for the control feed and HI-fortified feed (both 50 %), but a lower preference for NHI-fortified feed (31 %) compared to the control (69 %). The EMs were prepared by ionic gelation, using sweet whey and sodium alginate as base materials. Three types of EMs were developed: a control without iron (EMC), one with NHI (EM-NHI), and another containing a mixture of NHI and HI (EMplus). The EMs consisted mainly of non‑nitrogenous extract and protein. Structurally, the EMs were compact, and iron was successfully incorporated at concentrations ranging from 0.8 to 2.3 mg of iron per g. The type of EMs (EMC, EM-NHI, EMplus) did not significantly affect interaction time, consumption, or acceptability in pigs. However, the animals showed a clear preference for the whole EMs over their ground form. We conclude that encapsulation via ionic gelation enables the development of EMs capable of delivering NHI and NHI/HI mixtures, increasing pigs' acceptance of NHI. These findings suggest that EMs have potential as a delivery system for unpalatable compounds in both animals and potentially humans, pending further validation.