Development of quinoa protein-saccharide conjugates stabilized high internal phase Pickering emulsions for 3D...

High internal phase Pickering emulsions (HIPPEs) exhibit great potential in 3D printing and the delivery of hydrophobic compounds due to their semi-solid rheological properties and high oil phase volume. In this study, quinoa protein-saccharide conjugates were used to stabilize HIPPEs as 3D printing inks for the delivery of β-carotene. The quinoa protein-inulin conjugate (QP-Inu) demonstrated a larger three-phase angle approaching 90°, lower interfacial tension, and a higher absorption rate, resulting in a compact network structure with more tightly packed smaller droplets, as confirmed by particle size and confocal laser scanning microscopy (CLSM) analysis. All HIPPEs exhibited solid-like viscoelasticity and shear-thinning behavior. Among these, QP-Inu stabilized HIPPEs displayed higher viscosity and elasticity, superior thixotropic recovery rates, and enhanced 3D printability with improved accuracy and self-supporting ability. Furthermore, QP-Inu stabilized HIPPEs showed a better encapsulation capacity for β-carotene and superior storage ability, and stability against adverse environmental stresses, including pH, heating, salt ions, and oxidation. In conclusion, quinoa protein-saccharide conjugates can be promising candidates as stabilizers to form food-grade HIPPEs as new 3D printing materials and effective β-carotene delivery system.