Evaluation of physicochemical properties of starch-protein gels: Printability and postprocessing

The impact of physicochemical properties and printing parameters on starch-protein gel printability was evaluated to achieve stable 3D-printed gels suitable for individuals with special nutritional needs. The effect of postprocessing (oven/freeze-drying) on physical properties of printed gels was assessed. Corn starch (CS, 10%–15%) and salmon protein isolate (SPI, 2%–4%) were used to obtain stable printed gels; rheological and thermal properties were determined. The texture profile and dimensional stability of the printed gels were studied to determine the optimal printing parameters. The postprocessed gels were analyzed to evaluate their possible use as food with modified texture for dysphagic patients. Different CS-SPI concentrations influenced gel shear recovery by increasing protein denaturation temperature. The best dimensional and textural stability occurred with 15% CS and 3%–4% SPI using 0.91 mm nozzle diameter and 30 mm/s printing speed. Post-processed gels showed that freeze-drying managed to maintain excellent shape fidelity (94.66%–99.22%), while rehydrated gels had modified textures that made them suitable for use in dysphagic people. This study demonstrated that CS-SPI gels provide a promising alternative for 3D-printed foods especially for individuals with specific nutritional needs.