Fabrication of high internal phase emulsions (HIPEs) using pea protein isolate-hyaluronic acid-tannic acid complexes: Application of curcumin-loaded HIPEs as edible inks for 3D food printing.

Pea protein isolate (PPI)-hyaluronic acid (HA)-tannic acid (TA) ternary complexes were assembled using non-covalent interactions, their potential application in 3D printing and delivery of curcumin were investigated. As the HA-to-TA ratio in the complexes changed from 1:0 to 0:1, the oil-water interfacial tension first decreased and then increased, and the secondary structure of the proteins changed. The composition of the complexes (HA-to-TA ratio) was optimized to produce high internal phase emulsions (HIPEs) containing small uniform oil droplets with good storage and thermal stability. When the HA to TA ratio is 7:1 (P-H-T), HIPEs exhibited better viscosity, viscoelasticity, and thixotropy, which contributed to its preferable 3D printing. Moreover, curcumin-loaded HIPEs stabilized by P-H-T showed a high lipid digestibility (≈101%) and curcumin bioaccessibility (≈79%). In summary, the PPI-HA-TA-stabilized HIPEs have good potential to be 3D-printable materials that could be loaded with bioactive components.