High methoxy pectin regulates quinoa protein isolate-tannic acid complex to stabilized high internal phase emulsion via non-covalent interactions for enhanced 3D-printed foods

This study investigates the formation mechanism of the quinoa protein isolate (QPI), tannic acid (TA), and high methoxyl pectin (HMP) ternary complex, while exploring the potential of stable high internal phase emulsions (HIPEs) in 3D-printed food applications. The results indicate that QPI-TA (QT) complex and HMP primarily form the QPI-TA-HMP (QTH) ternary complex through hydrophobic interactions, hydrogen bonding, and electrostatic forces. By adjusting the ratio of QT to HMP, QTH complexes with high stability and zeta potential across a wide pH range can be achieved. HIPEs prepared with QTH complexes exhibit smaller oil droplet diameters, high hardness, resilience and mechanical properties, suggesting that they possess physiochemical characteristics suitable for edible ink applications. This was validated by using the HIPEs as edible inks to 3D print model food objects. This study advances the rational design of ternary biopolymer complexes as emulsifiers and offers valuable insights into the development of food inks.