Synergistic stabilization of oil-in-water emulsion gels by pea protein isolate and cellulose nanocrystals: Effects of pH and application to 3D printing

In this study, pea protein isolate (PPI) and cellulose nanocrystals (CNC) were used to prepare oil-in-water emulsions, and the effects of pH and the oil content on the properties of the emulsions were investigated. The microstructural analysis revealed that PPI and CNC formed complexes by electrostatic attraction at pH 3.0 and 4.5, which assembled a dense interfacial layer around the oil droplets, improving emulsification performance. Moreover, the emulsions at these pH conditions exhibited semi-solid gel properties when the oil content was increased to 75 wt%, with better viscoelasticity compared to pH 8.0 and high thixotropic recovery rates in rheological experiments. Printing of flat stacked models with these high internal phase emulsions had a deformation rate of around 5 %, indicating desirable shear resistance and fidelity. These findings would offer valuable insights for developing fat substitutes and their application as edible inks for 3D printing.