3D printing of starch-lipid-protein ternary gel system: The role played by protein

This study investigated the printability of a typical food ternary (starch-lipid-protein) gel system and revealed the critical role of protein. The results revealed that a higher content of α-helix and a lower content of random coil in proteins positively impacted the printing accuracy of the ternary gel system. Higher α-helix content in proteins increased the shear rate at the nozzle, ensuring smooth extrusion during 3D printing while also reducing the gel velocity and filament expansion, which led to smoother filament surfaces. Moreover, higher α-helix content and lower random coil content in proteins increased V-type crystalline structures, average molecular size (R_h), and amylose (AM) chains with 100 < X ≤ 1000, while decreasing amylopectin (AP) chains with 6 < X ≤ 12 in starch. These multi-scale structural changes increased A₂₃ content, leading to an increase in the storage modulus of the gel system and improving the mechanical property of 3D printed products, ultimately enhancing printing accuracy.