Effect of different iron ratios on interaction and thermodynamic stability of bound whey protein isolate

Abstract

Whey protein isolates (WPI) are known to have mineral-binding capacity to promote iron absorption. The aim of this study was to investigate the effect of iron ratio on the conformational structure of iron-bound whey protein isolate (WPI-Fe) and its thermodynamic stability. It was shown that the iron to protein ratio affects both the iron binding capacity of WPI and the iron valence state on the surface of WPI-Fe complexes. As the iron content increases, aggregation between protein molecules occurs. In addition, WPI-Fe nanoparticles have thermodynamic stability and Fe²⁺ has a high affinity with WPI for spontaneous exothermic reactions. This study demonstrates that WPI-Fe complexes can be used to efficiently deliver high-quality iron source (Fe²⁺) for future iron supplements.

Keywords: Conformational structure; Iron binding; Nanoparticle; Thermodynamic stability; Whey protein isolate.