Insights into the relationship between structure and rheological properties of starch gels in hot-extrusion 3D printing

Abstract

This work investigated the relationship between structure, rheological properties and 3D printability of starch. For this purpose, the structural evolution of various starch gels at different concentrations and printing temperatures was systematically studied. The mechanical strength (G', τ_y) and extrudability (τ_f) of CS and RS gels were used to determine its 3D printability. Furthermore, G', τ_y and τ_f were closely related to the structure of starch and starch gel network. Ascribing to compact and stable gel network, CS samples with 20% concentration at 70-75 °C printing temperature and RS samples with 15-20% concentration at 75-80 °C printing temperature displayed preferable printing values (G', τ_y and τ_f), indicating the suitability for HE-3DP. RS samples exhibited higher mechanical strength than CS samples and were more suitable to print owing to the formation of new crystal structure. Overall, this work provided important information for HE-3DP based foods with good printability.

Keywords: Hot-extrusion 3D printing; Printing conditions; Rheological properties; Starch gel; Structure.