Starch concentration is an important factor for controlling its digestibility during hot-extrusion 3D printing

Controlling the digestibility of starch by Hot-extrusion 3D printing (HE-3DP) is a new way to achieve personalized customization of starch-based foods. In this study, structural changes and in vitro digestibility of rice, wheat and potato starch gel materials at different concentrations during hot-extrusion 3D printing (HE-3DP) were studied, and their relationship was clarified. The results showed that increasing concentration of starch gel material could effectively resist the disruption of the ordered structure by hydrothermal and shear and then promoted the rearrangements of starch molecular chain. Interestingly, the newly formed ordered structure led to a significant increase in slowly digestible starch (SDS)+ resistant starch (RS) content of rice, wheat and potato starch-based printing samples at 25 % concentration, reaching 29.59%, 28.43% and 48.82%, respectively. Overall, starch concentration was found an important factor in regulating the ordered structure of printed samples and controlling its anti-digestibility during HE-3DP.