Food-grade Pickering emulsions and high internal phase Pickering emulsions encapsulating cinnamaldehyde based on pea protein-pectin-EGCG complexes for extrusion 3D printing

Plant protein-based edible Pickering emulsions (PEs) and high internal phase PEs (HIPPEs) for three-dimensional printing (3DP) and flavor compounds delivery were investigated. The effects of cinnamaldehyde proportions in oil phase (0%, 25%, 50%, 75% and 100%) on the storage stability, rheological properties, 3DP characteristics and interfacial behavior of PEs (oil phase volume φ of 0.52) and HIPPEs (φ of 0.83) were discussed. PEs and HIPPEs with cinnamaldehyde proportions of 0% and 25% prior to printing exhibited an excellent storage stability against coalescence and creaming after at 4 °C, 25 °C and 45 °C respectively for 30 days. The rheological data showed that PEs containing 0–25% cinnamaldehyde and HIPPEs containing 0–75% cinnamaldehyde had a viscoelastic solid-like response with high storage moduli and suitable viscosity, providing emulsion-based inks with strong support performance and smooth extrusion characteristics. For the printed cuboids, cylinders and turtles based on PEs, the distinct structural collapse and profile loss of fidelity occurred when the cinnamaldehyde proportion was over 25%. However, for HIPPEs with the increase of cinnamaldehyde proportion up to 75%, the printed lines, cuboids, cylinders and turtles presented acceptable 3D printability, superior gel strength and texture properties, which showed smooth surfaces, regular shapes and refined 3D structures. Besides, the loss rate of cinnamaldehyde as the flavor component reduced within 10.02 ± 0.01% and 11.29 ± 0.01% respectively during the 3DP processing. Plant protein-based PEs and HIPPEs could be potential materials for food 3DP with enhanced the flavor retention, thus providing guidance for the practical applications in food 4D printing.