Unravelling the synergistic effect of incorporation of inulin and high intensity ultrasound treatment on restructuring heat desiccated milk protein with 3D printing

This work highlighted the synergistic effect of high intensity ultrasound (HIUS) treatment (200, 400 and 600 W) and inulin addition (0, 2 & 4% w/w) on restructuring of heat desiccated milk semi-solids (HDMS) through hot melt extrusion 3D printing by investigating the rheological, structural, colour and molecular interactions induced in HDMS. Results demonstrated that HIUS and inulin synergistically improved the non-Newtonian pseudoplastic and viscoelastic behaviour, and extrudability of formulations. The combined effect of inulin addition and HIUS induced exposure of hydrophilic groups and development of new hydrogen linkages and resulted in a strong cross-linked network between milk protein and inulin. A profound effect on the secondary structure was linked to reduced α-helix and increased β-sheet in the formulations leading to improved structural integrity of the printed constructs. HDMS formulation with 4% inulin and 200 W HIUS treatment exhibited the best 3D printability. Significant variation (p < 0.05) in colour values of the printed constructs was reported.