Augmenting corn starch gel printability for architectural 3D modeling for customized food

Abstract

The advent of direct-ink-writing 3D printing in food processing highlights potential for innovation but underscores challenges with food-grade inks, notably their inadequate self-supporting properties post-extrusion that impede maintaining structural integrity and crating complex 3D forms. This challenge is particularly pronounced with starch—a key food ingredient. This study aims to bolster the printability of normal corn starch (NCS) through integration with pregelatinized (PG) high-amylose starch (G50 and G70, with 55% and 68% amylose contents, respectively) and proteins (soy, wheat, pea protein isolates, and whey protein). The PG starch was prepared by disorganizing the high-amylose starches in 33% CaCl2 solution and then precipitating them with ethanol. The formulation featuring an NCS/PG-G70/soy protein isolate ratio of 5:5:3 emerged superior, yielding enhanced formability, precise line printing, and robust self-support. This adapted starch-based gel facilitated the 3D printing of sophisticated structures, such as hollow and overhanging architectural forms, without necessitating chemical modification or a support bath. In vitro enzymatic hydrolysis tests on the printed constructs manifested approximately 50% resistant starch and 15% slowly digestible starch. These results suggest that the composite biopolymer ink developed in this study showcases not only superior printability but also boasts improved digestion-resistance. Thus, the findings from this research provide a foundation for developing food-grade inks capable of crafting customizable, intricately structured food products while conferring health advantages.