Exploring mussel adhesive protein as a natural Pickering emulsion stabilizer for 3D food printing applications

Mussel adhesive protein (MAP), a natural biopolymer rich in 3,4-dihydroxyphenylalanine (DOPA), has inspired extensive research into bioinspired materials, primarily targeting challenges in regenerative medicine and tissue engineering; however, its application in sustainable food formulations remains underexplored. In this study, MAP was combined with xanthan gum (XG) to stabilize Pickering emulsion gels with improved stability and 3D printability. Structural analyses confirmed that MAP and XG interacted mainly through hydrogen bonding and physical entanglement, enhancing network porosity and thermal stability. Accelerated aging tests showed that MAPXG1.6 maintained stability for 30 days without phase separation, while MAPXG0.8 exhibited Ostwald ripening. Rheological tests revealed shear-thinning behavior across all formulations. Notably, yield stress increased from 1.44 Pa (0 % XG) to 60.91 Pa (1.6 % w/v XG), accompanied by markedly enhanced thixotropic recovery, confirming the formation of a robust MAPXG network essential for extrusion fidelity. Water loss assays indicated that formulations with ≥1.2 % w/v XG retained significantly more moisture, supporting gel integrity. Extrusion-based 3D printing further demonstrated that emulsions with 1.2–1.6 % w/v XG produced high-fidelity cubes and hollow cylinders, maintaining structural stability for at least 5 days, whereas ≤0.8 % w/v XG samples collapsed rapidly. These findings highlight that rational tuning of XG concentration confers MAP-stabilized emulsions with long-term stability and reliable printability, offering a promising marine protein-based platform for sustainable 3D food inks.