Valorization of salmon industry by-products: Evaluation of salmon skin gelatin as a biomaterial suitable for 3D food printing

A strategy for effective utilization of food wastes is a key challenge nowadays. In this study 3D printing technology was used to develop a suitable material based on salmon industry by-products. The objective of this work was to evaluate the printability of salmon skin gelatin gels (SGGs) at different concentrations (2%, 5%, 8%, 11%, and 14%) by studying their physical properties (rheological, textural, and printability) and analyzing dimensional stability. Static and dynamic tests provided the rheological characterization of salmon gelatin extracted under optimum conditions. The texture profile and printability of SGGs was studied by determining the shear modulus and extrude hardness. The deviation in the three dimensions (length, width, and height) of the printed SGG cubes was also determined. Results showed that SGGs exhibited shear thinning and viscoelastic behavior in which the elastic component predominated. Texture property analysis together with printability analysis showed that 8% SGG could be easily extruded and could form stable structures after printing. The most suitable biomaterial for extrusion-based 3D printing was the 8% SGG because the printed objects fitted the designed 3D models and maintained their dimensional stability over time. This work provides insight into the suitability of using salmon gelatin for 3D food printing applications.