Modulation of DBS/Zein/Pectin Nanoparticle Properties by Calcium Ions: Physicochemical and Emulsifying Insights

This study investigated the effects of Ca²⁺ ions on the physicochemical properties of DBS/zein/pectin (DZP) ternary composite nanoparticles by adding varying concentrations of Ca²⁺ during particle formation. Ca²⁺ ions reduced electrostatic repulsion between colloidal particles, causing collisions and aggregation, which increased particle size. Additionally, Ca²⁺ ions decreased α-helices and increased β-sheets in the zein molecular chains, weakening interactions between zein and other components, and reducing the thermal stability of the composite particles. At high Ca²⁺ concentrations, phase separation occurred, with the crystalline structure nearly disappearing. Ca²⁺ ions neutralized surface charges, decreased colloidal particle wettability, and reduced emulsifying capacity. Emulsions prepared with these particles showed that Ca²⁺ addition intensified the aggregation of composite particles on the emulsion droplet surface, resulting in pronounced phase separation and reduced emulsion stability. Overall, these results demonstrate that Ca^{2 +} plays a key regulatory role in governing the structure-property relationships of DZP ternary composite nanoparticles. This study provides mechanistic insight into ion-mediated regulation of protein-polysaccharide systems and highlights the potential of DZP nanoparticles as calcium-responsive carriers for food-related delivery applications.