This study addressed the potential of 3D printing as a processing technology for delivering personalized healthy eating solutions to consumers. Extrusion-based 3D printing was studied as a tool to produce protein- and dietary fibre-rich snack products from whole milk powder and wholegrain rye flour. Aqueous pastes were prepared from the raw materials at various ratios, grid-like samples printed from the pastes at ambient temperature and the printed samples post-processed by oven baking at 150 °C. Printing pastes were characterized by rheological measurements and the baked samples by X-ray micro tomography, texture measurements and sensory analysis. All formulations showed good printability and shape stability after printing. During baking, the milk powder-based samples expanded to a level that caused a total collapse of the printed multiple-layer samples. Shape retention during baking was greatly improved by adding rye flour to the milk formulation. Sensory evaluation revealed that the volume, glossiness, sweetness and saltiness of the baked samples increased with an increasing level of milk powder in the printing paste. A mixture of milk powder and rye flour shows great potential as a formulation for healthy snack products produced by extrusion-based 3D printing.

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Rapeseed press cake was upcycled as a protein-enriched ingredient through dry fractionation. The protein-enriched fraction contained higher amounts of phytic acid compared to press cake, and phytase treatment was applied to decrease the phytic acid content from 6.8 to 0.5%. The effect of phytase treatment leading to the release of cations was also mimicked by extrinsic calcium addition. Both phytase treatment and calcium addition significantly improved the heat-induced gel properties but had a minor effect on protein solubility and dispersion stability at pH 8. Water and protein holding capacities of the gels were the highest for the phytase-treated sample (91 and 97%, respectively), followed by the sample with added calcium (86 and 94%, respectively) and control sample (60 and 86%, respectively). Gel firmness followed the same pattern. Scanning electron microscopy images revealed an interconnected structured network in the phytase-treated gel, while in the control gel, a more rigid and open structure was observed. The improved gelation properties resulting from the phytase treatment suggest that the protein and soluble dietary fibre-enriched rapeseed press cake ingredient serve as a promising raw material for gelled food systems. The positive effect of calcium addition on gel properties proposes that part of the improvement observed after phytase treatment may be caused by cations released from phytate.