Effect of stearic acid on the microstructural, rheological and 3D printing characteristics of rice starch.

The aim of this study was to investigate the changes of the microstructural, rheological and printing properties of rice starch-stearic acid (SA) paste during the hot-extrusion 3D printing (HE-3DP). The results showed that starch chains could complex with SA to form V-type crystalline structure and its molecular kinematic behaviors were changed under shear force, and crystalline structure were then embedded and rearranged to constitute an ordered sea-island structure, thus improving the rigidity and dynamic storage modulus of network structure, leading to the increased layer number. Interestingly, with the increase of SA addition, the network structure became weakened and the viscosity decreased which might due to the destroyed continuity and the breaking of entanglement and hydrogen bonding between starch chains, and finally impairing the printing accuracy of objects. Overall, this study provided important information for the application of lipid in the preparation of starch-based food by HE-3DP.