Rheological optimization of low-methylated pectin–xyloglucan–cellulose nanocrystal composites for 3D printing: stability and printability

Abstract Extrusion-based 3D printing of biobased hydrogels depends on ink rheology, requiring strong shear-thinning for smooth flow and sufficient yield stress to maintain shape after deposition. Polysaccharides from plant cell walls (PCW) are known as sustainable, structurally stable materials, but their three main components—cellulose, hemicellulose, and pectin—have not been combined for this purpose. Here, a bioink composed of cellulose nanocrystals, xyloglucan, and pectin is developed for extrusion printing using response surface methodology (RSM) with material characterization. Systematic variation in composition reveals clear relationships between rheology, print fidelity, and mechanical performance. FTIR confirms composition-dependent hydrogen bonding within inks and printed structures, along with formulation-dependent colour changes. Among the components, pectin has the strongest influence on rheology. Biobased inks with equal proportions of all three components (3% and 5%) show optimal printability. Compared to 3%, 5% formulations exhibit higher viscosity and yield stress, improving shape retention and pore definition. Ionic cross-linking does not significantly affect geometry but enhances mechanical strength. These findings highlight multicomponent plant polysaccharide inks as tunable, sustainable materials for extrusion-based additive manufacturing, mimicking natural PCW assembly.