Enhanced printability of food-grade edible inks: Emulsions formulated with modified pea protein and sodium alginate

The 3D printing of foods has grown in interest recently due to its ability to create customized or personalized food products. This study focused on the creation of stable high internal phase Pickering emulsions (HIPPEs) for application as edible inks in 3D food printing. These concentrated oil-in-water emulsions were innovatively prepared using modified pea protein isolate (PPI) and sodium alginate (SA) complexes as stabilizers. Pea protein isolate was used in its commercial form (C-PPI) or in a high-pressure homogenized and ultrasonically modified form (HU-PPI). Four types of stabilizers were used to formulate the HIPPEs: C-PPI, HU-PPI, C-PPI-SA, and HU-PPI-SA. The particle size, microstructure, rheology, stability, and 3D printability of the resulting emulsions were characterized. HIPPEs formed using HU-PPI-SA complexes had the smallest particle diameters (<50 μm), as well as a more compact microstructure than those formed using the C-PPI-SA. Rheologically, the HU-PPI-SA stabilized HIPPEs had a higher storage modulus (500 Pa) and apparent shear viscosity (1000 mPa·s), which enhanced their 3D printability. Shapes printed with these emulsions maintained their structural integrity for up to 24 h, indicating the potential of HU-PPI-SA stabilized HIPPEs as edible inks for 3D food printing applications because of their enhanced stability, printability and rheological properties. This study provides new information that could facilitate the development of edible inks that combine good printability and nutritional value to achieve customized nutrition and efficient industrial food production.