Physicochemical stability of Pickering emulsion stabilized with spherical and fibrous iron ions loaded whey protein isolate/gum Arabic complexes

Iron deficiency is widespread worldwide and shows significant impact on human health. The direct iron supplementation produced little effect because of the physicochemical properties and gastrointestinal stimulation of iron ions, and thus the biomolecules loaded iron delivery systems developed rapidly. Pickering emulsions (PEs) could be stabilized by colloidal particles and provide potentials for delivery of various bioactives effectively and simultaneously. Here, the feasibility of PEs stabilized with Fe3+ loaded colloid granules for iron delivery was explored. The binary WPI-GAFe3+ (whey protein isolate/containing Fe3+ gum arabic) complexes with spherical (WGS) or fibrous (WGF) morphology were constructed by adjusting the reaction conditions of protein aggregation. Compared to GAFe3+, WGS and WGF exhibited better interfacial activity in terms of the lower interfacial tension and the competitive interfacial adsorption with the pre-adsorbed T-80 and sodium caseinate, and favorable physical stability on PEs, as well as the significant retardation of the pro-oxidant activity of lipids by Fe3+. WGS-PE exhibited more uniform droplets, lower droplets mobility, less variation of turbiscan stability index and lower content of lipids oxidation products than that of WGF-PE. This may be related to the spherical assembled structure and inside entrapped GAFe3+ of WGS that could adsorb onto the droplets interface tightly and neatly, accordingly increase the physical stability of PEs, but also prevent the leakage of iron ions, thus reducing the lipid oxidation. It is suggested that PEs would be a feasible and effective iron ions delivery platform, which would provide a reference for designing iron fortification in food.