Effect of amylose content in corn starch on the rheological properties, 3D printability, and in vitro digestive properties

High amylose corn starch (HACS) is a promising functional food ingredient, resisting digestion. Amylose content matters for starch gelatinization, gel formation, and 3D printing. It also links to the content of resistant starch (RS). Achieving optimal 3D printing with ideal digestion resistance challenges starch-based food printing. This study sought the optimal amylose range balancing these traits. Four corn starches (amylose: 28.68%-70.06%) were tested for rheology, printing accuracy, RS, structural features. HACS-1946 (58.84% amylose) had low printing deviation (6.59% in length) and high RS (33.93%, compared to 10.09% in 28.68% amylose normal starch), balancing resistance and formability. In contrast, HACS-K130 (66.13%) and HACS-1945 (70.06%) had significant printing defects from rapid retrogradation. Gelatinization and 3D printing reduced RS by disrupting crystallinity, but only changed physical aggregation. These findings suggest moderate amylose content balances formability and nutritional benefits, offering insights for developing starch-based 3D products with controllable digestibility, precision, and functionality.