Xanthan gum-assisted tailoring and characterization of heat desiccated milk solids-based dysphagia-friendly 3D printing formulations.

This study investigated the role of xanthan gum (XG) in modulating 3D printability, rheological behaviour, structural features, tribological, and dysphagic attributes of formulations prepared from heat-desiccated milk solids (HDMS) added with cane sugar. XG was incorporated at 0.5, 1.0, and 1.5% (w/w) in HDMS with total solids (TS) of 55 and 60% and cane sugar concentrations of 20 and 30%. All the formulations exhibited shear-thinning, viscoelastic gel-like behaviour, with XG addition notably enhanced yield stress, storage modulus, and shear recovery. Among them, formulation F11 (60% TS HDMS, 20% sugar, 1.0% XG) demonstrated superior printing precision, shape fidelity, and extrusion control, owing to its elastic structuring and flowability. Tribological analysis showed that XG reduced friction coefficients, implying enhanced oral lubrication. Particle size distribution, SEM, and CLSM confirmed denser, more uniform protein-polysaccharide networks at higher XG levels, while FTIR, NMR, and DSC revealed enhanced protein-hydrocolloid interactions, reduced water mobility, and XG-induced plasticization effects. Correlating with network densification, texture profile analysis further indicated that XG incorporation increased hardness, cohesiveness, and chewiness attributes. Several XG-containing formulations were classified under IDDSI levels 5-7, underscoring their potential application in dysphagia-friendly diets. These findings highlight the multifunctional role of XG in tailoring rheology, lubrication, and microstructure of dairy-based 3D printing inks. By establishing an optimal composition window, this work provides a practical framework for the dairy industry to design customizable, structurally stable, and dysphagia friendly 3D-printed products.