In vitro oxidation and digestibility profiles of iron-loaded whey protein isolate/gum Arabic complexes with different morphologies

Abstract

This study was designed to investigate the promotion of oxidation of lipids in oil-in-water (o/w) emulsions and digestive properties of the bionic dynamic gastrointestinal system of whey protein isolate (WPI) and gum arabic (GA) complexes loaded with iron ions, which were fabricated previously and shown as WPI/GA_Fe³⁺ nanoparticles (WGS) and WPI/GA_Fe³⁺ fibers (WGF). Compared with emulsions containing Fe³⁺ and GA-loaded complex (GA_Fe³⁺), WGS and WGF greatly improved the oxidative stability of lipids along with the reduced lipid oxidation products and volatile compounds, attributed to the encapsulation of iron ions. During the bionic dynamic gastrointestinal digestion, the iron ion release of WGF was significantly higher than that of WGS, probably due to different assembled internal structures. Accordingly, two proposed WPI/GA_Fe³⁺ complexes with different morphologies are expected to be developed as novel stable iron fortifiers with delayed lipid oxidation and controlled iron-ion release in food emulsions.