Three-Dimensional Printing of Sustainable Food Inks from Fruit By-Products: Rheology, Printability, and Sensory Evaluation

The current study explores a sustainable strategy for repurposing fruit processing waste through the development of a 3D printable ink derived from muskmelon rind, sugar, lemon peel powder, and sodium alginate. The research focuses on extrusion-based 3D food printing, which is an emerging additive manufacturing technology that enables the precise layer-by-layer fabrication of complex, customisable edible structures. The formulations with varying alginate concentrations (1.2%, 1.8%, and 2.4% w/w) were optimised for extrusion-based 3D printing. Textural analysis and rheological profiling, represented as critical parameters for smooth extrusion, shape fidelity, and post-print stability, were performed to establish a correlation between material properties and their suitability for 3D printing. Shear-thinning behaviour and adequate structural integrity of the developed formulations confirmed their compatibility with the 3D printing process. Sensory evaluation of the 3D-printed product revealed favorable taste and appearance, indicating potential for consumer acceptance. Among the tested formulations, the blend containing 1.8% sodium alginate demonstrated optimal printability, especially when extruded through a nozzle diameter of 1.04 mm. Aligned with the principles of circular economy, this study demonstrates the potential of 3D food printing as a tool offering a scalable and customisable solution to transform agri-food waste into innovative, value-added food products that contribute to environmentally conscious processes for the future of food manufacturing.