Ultrasound-assisted chelation of whey protein isolates with iron: Effects of power variation on protein conformation and binding efficacy.

It is widely recognized that whey protein possesses a mineral-binding capacity that enhances dietary iron absorption, and Ultrasound is a non-thermal physical modification technique that can induce changes in protein conformation. However, the effect of ultrasound treatment on the mineral-chelating ability of whey protein isolate (WPI) remains unclear. Therefore, we prepared whey protein isolate‑iron binary complexes (UWPI-Fe) using ultrasound-modified WPI and investigated the effects of ultrasonic power on their structural conformation and chelating effect. Through structural characterization, iron-binding capacity determination, surface iron valence analysis and solubility analysis, we found that sonication induces the denaturation of WPI and alters its iron-binding properties. The results showed that at 30 % ultrasonic power, solubility (95.41 %) and iron chelating capacity (90.7 mg/g of protein) were significantly enhanced. Notably, the surface Fe2+ content of UWPI-Fe complexes significantly exceeded that of non-ultrasonicated WPI-Fe complexes, peaking at 50.89 % at 40 % ultrasonic power. Furthermore, UWPI-Fe complexes demonstrated superior duodenal bioavailability compared with conventional FeSO₄. It was confirmed that ultrasonic modification could effectively improve the iron chelating properties of WPI, and these findings highlight the potential of ultrasound to develop high-quality iron source (Fe2+) delivery systems for food and pharmaceutical applications.