Rapid-gelating starch from potential ginger processing waste: Multi-scale structural analysis enabling high-precision 3D printing for health-focused food applications

Conventional 3D-printing gels based on synthetic polymers are limited by poor edibility, inefficient environmental degradation, and possibly high costs, which limit their application in food and eco-friendly applications. Bio-edible resources present a promising alternative for 3D printing materials. In this study, we identified starch exhibiting rapid gelation at low concentrations (6%) and high printability from five varieties of ginger. A comprehensive analysis of the multi-scale structures and physicochemical properties of these starches reveals that Curcuma phaeocaulis Valeton starch (CPS) and Curcuma longa L. starch (CLS) exhibit unique multiscale structures, enabling rapid gelation (1-2 min) and achieving 95.40-96.08% printing precision at 6% concentration. The multi-scale structure analysis shows that higher amylose content and short amylopectin chain facilitate physical entanglement of molecular chains, accelerating rapid gelation post-pasting, which is 10-21 times faster than traditional starches such as potato starch. Rheological tests confirm stable gel networks (G′ > Gʺ during cooling) and a suitable closed-pore structure that mitigates dehydration shrinkage, enhancing printing precision. Notably, CLS showed low digestibility (53.79%) and high resistant starch content (44.55%), highlighting its potential for healthy food applications. This work pioneers a waste-to-3D printing material strategy by elucidating the rapid starch gelation mechanism through multi-scale structural design, thereby enabling high-value utilization of agricultural waste and advancing precision health food manufacturing with novel functional materials. • The yield of ginger starch achieved 71.48%; • Rapid gelation (1-2 min) synergizes with >95% 3D printing precision; • High resistant starch content (31.1-46.84%) attained; • Multi-scale structure-property correlation mechanisms systematically validated.