Investigation of the structure, rheology and 3D printing characteristics of corn starch regulated by glycyrrhizic acid

Abstract

This study aimed to construct a novel corn starch-glycyrrhizic acid (CS-GA) ink and systematically investigate the effects of GA on the water distribution, microstructure, rheology and 3D printing properties of CS hydrogels. The results showed that the CS chains could form strong hydrogen bonds with GA molecules, inhibit the formation of short-range ordered structure of CS and reduce the content of B-type starch. The low-field nuclear magnetic results showed that the introduction of GA could increase bound water content in CS-GA hydrogels. With the increase of GA content, the CS-GA hydrogel changed from CS-dominated to a GA-dominated gel network system. Rheological results showed that all samples exhibited typical shear thinning behavior. High GA concentration was beneficial to increasing the self-supporting properties and thixotropic recovery of CS-GA hydrogels. Compared with the pure CS hydrogel, the 3D printing characteristics of CS-GA hydrogels were significantly enhanced due to the increased bound water content and the enhancement of rheological properties. At 40 % GA content, CS-GA hydrogel showed the highest printing accuracy of 96.4 % ± 0.30 %. The printed product could perfectly replicate the preset model. Therefore, this study provided a theoretical basis for regulating starch's rheology and 3D printing characteristics and developing novel food-grade 3D printing inks.

Keywords: 3D printing; Corn starch; Glycyrrhizic acid; Hydrogels; Rheological properties.