Whey protein hydrolysate fibrils-dextran delivery iron oxides: stability and bioavailability

Iron deficiency anemia (IDA) is one of the most common nutritional disorders worldwide. However, traditional iron supplement often induces adverse gastrointestinal effects (e.g. nausea, vomiting, abdominal pain) due to their gastrointestinal irritation and poor bioavailability. To overcome this defect, we designed an antioxidative whey protein hydrolysate fibril-dextran (WPHF-DEX) complex system, which can delivery low-irritant and highly biocompatible iron oxide by in-situ co-precipitation and enhancing iron bioavailability. After mixing with WPH and grafting with dextran, the antioxidant of WPHF-DEX was significantly improved. Moreover, the more iron oxide binding sites of fibril was exposed. FTIR spectroscopy showed that the WPHF-DEX can bind to iron oxide via a coordination bond, and the WPHF-DEX‑iron oxide (WPHF-DEX-Fe) complex had good stability. In vitro digestion indicated that the WPHF-DEX could maintain the oxidation state of iron in the intestine, reducing the irritation to the gastric mucosal. Furthermore, this stabilized iron form and WPHF-DEX encapsulation significantly enhanced subsequent absorption by the intestine. The iron bioavailability of WPHF-DEX-Fe was 1.4-folds than that of FeSO₄in vitro without observable cytotoxicity. Therefore, the WPHF-DEX composite system can become a novel iron oxide delivery system with high loading capacity and bioavailability.