Rheology-texture interplay in alginate–nanocellulose gels for high-fidelity edible 3D-printing

The interplay between rheology and texture is critical in designing edible inks for 3D food printing, as rheology governs extrusion behaviour while texture influences the structural stability of printed constructs. In this study, alginate-cellulose nanocrystal (CNC) composite inks were developed with tunable rheological, textural, and printability characteristics. CNCs extracted from cotton via acid hydrolysis exhibited a needle-like morphology and surface potential difference of 48.2 mV. Composite gels formulated with alginate (5–25% w/v) and CNCs (2.5–15% w/v) showed matrix-dominated rheological behaviour, where increasing alginate concentration significantly enhanced storage modulus (G′), loss modulus (G″), and viscosity, while CNCs provided secondary, concentration-dependent reinforcement. Regression and response surface analyses identified alginate as the primary contributor to viscoelasticity, with CNCs improving resistance to deformation at intermediate concentrations. The addition of sugar and salt to produce sweet and savoury inks further modified rheological and instrumental texture parameters. Correlation analysis and principal component analysis (PCA) revealed formulation-dependent rheology–texture relationships, including associations between hardness and gumminess in sweet gels and between adhesiveness and viscosity in savoury gels. Printability evaluation demonstrated successful extrusion of grid structures, unsupported spans, and complex geometries, with composite inks showing improved shape fidelity and reduced collapse compared to alginate-only formulations. Overall, the study defines how formulation-dependent rheological and texture parameters can help in designing edible inks for 3D-food printing.