Construction of 3D printable native-modified corn starch composites gels as dysphagia diet: Crucial role of modified starch.

The citric acid (10 %) was blended with corn starch (CS) to prepare dual-modified corn starch (MS) using extrusion technology, and varied contents (10 %, 20 %, 30 %, 40 % and 50 %) of MS accompanied with CS to develop a 3D-printed gel for people with dysphagia. Results showed that incorporating MS reduced the peak viscosity of CS from 3032 cP to 1348 cP, as well as decreased hardness and viscoelasticity of CS gel. The addition of MS inhibited the flow of water molecules, but made the water molecules more evenly distributed in gels. Microstructure observation illustrated that the CS-20 %MS and CS-30 %MS gels showed more compact microporous network among these gels. The microstructure of pure CS and CS-MS10 % gels mainly stabilized by hydrogen bonds, while there were ester bonds in the other CS-MS gels. Additionally, the incorporation of MS enhanced the relative crystallinity and short-range ordered degree of CS gel from 5.63 % and 1.74 to 6.56 % and 2.18. The CS-MS gels exhibited better 3D printability than CS gel, and the IDDSI testing demonstrated that the 20 % and 30 % MS formulation was more suitable for people suffering from dysphagia. Overall, these findings provided a strategy for designing dysphagia foods with satisfactory printability, which beneficiated to the widespread use of native and modified corn starch.