Rheology as bridging component: Towards high-quality meat analogues

Over the last decade, the food industry has been transitioning towards alternative protein sources, and simultaneously, research on extrusion-based 3D food printing (3DFP) has emerged. Besides new opportunities, combining the fields of alternative proteins and 3DFP also comes with significant challenges, especially regarding rheology. As protein- and fat-rich inks for extrusion-based 3DFP do not exhibit favourable printing properties of their own, hydrocolloids are often added. However, the rheological aspect of 3DFP is still not well understood for non-native printable inks. Additionally, the literature currently considers four printing stages where different rheological properties are thought to play a role in each stage. However, a real consensus on the main important rheological parameters is not yet found. Overall, previous studies either did not (i) investigate rheology, (ii) extract meaningful data, (iii) consider tuning the ink’s rheology, or (iv) relate rheology to the 3D printing process. Therefore, this work focuses on increasing the knowledge of the rheological behaviour of plant-based protein-rich inks on all four fronts. This allows the establishment of efficient procedures and testing methods. Mainly step-change responses and flow curves are assessed, resulting in meaningful data regarding shear thinning, viscoelastic and thixotropic behaviours. This work aims at (i) extracting relevant rheological data to improve rheological comprehension of non-native printable inks and (ii) proposing meaningful relations between rheology and the 3DFP process of protein-based inks. In summary, this work provides insight into printability, rheology, and the relations between them. Particularly, this can help achieve high-quality alternative meat products via extrusion-based 3DFP.