Preparation of Pickering emulsion gel stabilized by tea residue protein/xanthan gum particles and its application in 3D printing

Gel-like Pickering emulsion (PE) stabilized by the complexes of tea protein (TP) and xanthan gum (XG) (0.0%–2.5%) was fabricated as ink for 3D printing. The TP/XG complex was firstly characterized. Its zeta potential was below −30 mV, and TP's secondary structure and microstructure were changed with XG addition. Afterwards, gel-like PE was developed at pH 7, 70% oil fraction, and 3% TP/XG concentration. Results indicated that the oil droplet was surrounded by TP/XG particles, and its size was decreased when XG concentration increased. Water holding capacity, gel strength, viscosity, and mechanical strength of PE gel were improved after XG incorporation. 3D printing tests indicated that the PE gel with XG over 1.5% showed desirable smooth extrusion and excellent self-supporting capability to maintain the designed shape structure. This study provides new insights on the development of 3D printed exquisite/appealing decoration structure on cake, with potential to replace traditional hydrogenated cream.