Fabrication of emulsion gels with oyster protein particles through depletion attraction for 3D printing

3D printing is revolutionizing the creation of specialized foods, offering customizable textures for the elderly and personalized nutrition preferences. However, the availability of edible and low-fat emulsion gels with the desired shear-thinning behavior and elastoplastic rheological properties, crucial for direct-write 3D printing, remains limited. In this study, a novel approach for fabricating a low-fat, 3D printable oil-in-water emulsion gel using oyster protein particles (OPPs) through exploiting depletion attraction was developed. We discovered that the concentration of OPPs played a pivotal role in promoting the production of depletion attraction between droplets, which facilitated the formation of self-standing and elastoplastic emulsion gels suitable for 3D printing. Moreover, we observed that increasing homogenization pressure, pHs and ionic strengths contributed to the flocculation of oil droplets and the enhancement of rheological properties in the emulsions. By understanding the properties of OPPs and their roles in continuous phases and on interfaces, OPP-based 3D printable material is created for the first time. This novel approach can be applied by leveraging depletion attraction and opens up possibilities for using protein particles to produce personalized and nutritious foods by 3D printing.