Impact of starch amylose and amylopectin on the rheological and 3D printing properties of corn starch

This study evaluated the influence of the amylose and amylopectin on the physicochemical properties and printing performance of corn starch gels. Amylose in starch-based gels enhances their storage modulus and the support performance of printed products by promoting the formation of cross-linked gel structures and crystalline structures. However, the higher amylose content in starch gels makes extrusion difficult, resulting in intermittent extrusion in 3D printing. Despite the increased shear-thinning ability of high-amylose starch, its low water retention capacity leads to water loss and rough printed morphology. Additionally, starch with 72 % amylose content exhibits insufficient adhesive properties for effective layer bonding, negatively impacting structural integrity. While gels with 72 % and 56 % amylose content demonstrate higher viscosity and enhanced mechanical properties, their poor adhesion limits the quality of printed layers. Conversely, waxy starch gel demonstrates continuous extrusion and adhesion but lacks adequate support. The 27 % corn starch gel achieves the highest 3D printing accuracy at 88.12 %, suggesting an optimal amylose-amylopectin ratio for desired ink material performance. These findings enhance our understanding of the relationship between amylose content in starch and 3D printing performance, providing a theoretical basis for the development of starch-based printing products.