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.