Standardisation of encapsulation of iron fortified whey protein concentrate using alginate hydrogel

Abstract

Iron deficiency anemia remains the most prevalent nutritional disorder globally, highlighting the urgent need for effective iron fortification strategies. Encapsulation of iron in food-grade matrices offers a promising approach to improve stability, bioavailability, and sensory acceptance. This study aimed to standardize the encapsulation of iron-fortified whey protein concentrate (WPC-Fe) using alginate hydrogels through ionotropic gelation. WPC-Fe complexes were prepared at a protein-to-iron ratio of 40:1 and incorporated into alginate solutions (1.0-2.0%, w/v), followed by cross-linking in calcium chloride solutions (3%, 5%, and 10%, w/v) at different pH levels (3, 5, and 7). The stability and bursting behavior of the beads were evaluated in 0.1 M phosphate buffer (pH 7). Results showed that no bead formation occurred at pH 3, while stable beads were formed at pH 5 and 7. Beads cross-linked with calcium chloride concentrations of 3% to 10% exhibited improved structural integrity. In phosphate buffer, most beads burst within 1 h, except for a few formulations prepared with 2% WPC-Fe/alginate and higher calcium chloride concentrations at pH 5 and 7. Comparable bursting behavior was observed for WPC and WPC-Fe beads, suggesting that protein-iron interactions did not enhance resistance against phosphate-induced destabilization. The findings demonstrate that pH and calcium chloride concentration are critical factors influencing bead formation and stability.