Effect of rheological properties of potato, rice and corn starches on their hot-extrusion 3D printing behaviors

In this study, the relationship between rheological properties and printability of three types of starch (potato, rice and corn starch) for hot-extrusion 3D printing (HE-3DP) were systematically investigated. Each starch sample showed a shear-thinning behavior, self-supporting property, as well as the feature of a substantial decrease at higher strains and a recovery at lower strains in storage modulus (G′), which indicated the suitability of starch for HE-3DP. Besides, the flow stress (τf), yield stress (τy), and G′ increased with a higher starch concentration. We found that starch suspensions with concentrations of 15-25% (w/w) heated to 70-85 °C possessed preferable values of τf (140-722 Pa), τy (32-455 Pa), and G' (1150-6909 Pa) for HE-3DP, which endowed them with excellent extrusion processability and sufficient mechanical integrity to achieve high resolutions (0.804-1.024 mm line width). Overall, our results provided useful information to produce individualized starch-based food by HE-3DP.