A cholecalciferol-loaded emulsion stabilized by a pea protein isolate–inulin complex and its application in 3D food printing

In this study, we formulated Pickering emulsions incorporating cholecalciferol using pea protein isolate (PPI)-inulin complexes, applying them in three-dimensional food printing to produce nutritionally fortified printed food products. Remarkably, the incorporation efficiency (IE) of cholecalciferol ranged from 95.69% to 102.37%, indicating no cholecalciferol loss during emulsion preparation. Turbidimetric assays revealed that in emulsions stabilized by PPI with high-oil-content, creaming formation was noticeable in the upper layer. However, the PPI-inulin complex effectively inhibited phase separation, maintaining a stable emulsion system. Furthermore, rheological analysis demonstrated that the PPI-inulin complex significantly enhanced the viscoelastic properties of the food inks used for 3D printing. Additionally, food ink viscosity increased gradually with increasing oil content. While most food inks exhibited excellent printing quality, it is worth noting that excessively high viscosity in the food ink resulted in intermittent flow through the printing nozzle, leading to printing failure with low printing resolution.