Improved oxidation stability, 3D printing, and β-carotene delivery performance of high internal phase Pickering emulsions using quinoa protein-inulin/chlorogenic acid ternary complexes

This study aimed to investigate the oxidation stability, 3D printability, and β-carotene delivery performance of high internal phase Pickering emulsions (HIPPEs) stabilized by quinoa protein-inulin (QP-Inu) conjugates and chlorogenic acid (CA) ternary complex. Compared with QP-Inu, the ternary complex (QP-Inu/CA non-covalent complex and QP-Inu-CA covalent complex) showed a rougher surface, a higher three-phase angle close to 90°, lower interfacial tension, and an increased absorption rate at the oil-water interface. From particle size and confocal laser scanning microscopy (CLSM) analysis, HIPPEs stabilized by the ternary complex exhibited a compact gel network structure with more tightly packed smaller droplets. This microstructure contributed to their improved oxidation stability from generation of lower levels of primary and secondary lipid oxidation products, enhanced 3D printing capabilities from higher viscosity and elasticity, superior thixotropic recovery rates, and increased printability with improved accuracy and self-supporting ability, as well as enhanced β-carotene delivery from higher encapsulation capacity and bioavailability. These findings suggested that covalent interactions enhanced the interfacial nanoparticle layer, while non-covalent interactions endow greater antioxidant activity to the QP-Inu, providing insights for the designing of multifunctional HIPPEs with broad application potential.