Improving the printability of watermelon rind using pectin: 3D printing optimization for the development of gummies

Abstract This study explores the innovative use of 3D printing to repurpose fruit processing waste, focusing on the development of vegan gummies from watermelon rind. Gummies were formulated with watermelon rind puree, sugar, and varying pectin concentrations (0%, 5%, 10%, 15%, and 20% w/w) to optimize the hot extrusion 3D printing process. Material characterization, including textural, rheological, and thermal analyses, was conducted to establish correlations with 3D printability. The effects of printing parameters, speed (600, 800, and 1000 mm/min), nozzle diameter (0.6, 0.84, and 1.22 mm), and temperature (60, 80, and 100°C) were evaluated. The optimized formulation containing 10% using high methoxyl pectin demonstrated good printability, achieving the best results with a nozzle diameter of 0.84 mm, a temperature of 80°C, and a printing speed of 800 mm/min. Sensory evaluations indicated a higher consumer preference for 3D‐printed gummies than their non‐3D‐printed counterparts. This study highlights the potential of 3D printing in promoting sustainable practices through waste valorization and upcycling, aligning with the United Nations' Sustainable Development Goals (UN‐SDGs). This research study provides insights into the development of a novel value chain from a range of fruit and vegetable discards which are otherwise considered as zero value wastes. Importantly, 3D printing supports excellent levels of customization, promoting wider product ranges and improving consumer acceptability of agricultural by product/waste‐sourced products.