Effect of Temperature Sensitive Colloid on 3D Printing and Curing Properties of Corn Starch

Objective: To assist the molding and curing of starch in 3D printing, and to reveal the change law of curing properties of different hydrocolloid-starch systems based on the phase-change characteristics of temperature-sensitive hydrocolloids. Methods: Three hydrocolloids, low-acyl gellan gum, gelatin, and κ-carrageenan, respectively, were mixed with corn starch at different ratios for evaluating their rheological properties. The printability and curing performance were evaluated by printing cylinder and hollow sphere models, testing force-displacement curves, temperature sweep rheology, whole-texture analysis and microstructure observation. Results: When gellan gum and κ-carrageenan were added at 2%~4% and gelatin at 0%~2%, the system had suitable rheological properties and good printability. The products with 4% gellan gum and 4% κ-carrageenan showed remarkable plasticity and better curing effect. Whereas the products with gelatin was not significantly plastic and cured. The curing temperature of gellan gum-starch system and κ-carrageenan-starch system were between 35~43 ℃ and 30~40 ℃ respectively, meanwhile, the curing temperature and speed increased with the increase of hydrocolloids content. However, as the gelatin content increased, the curing temperature decreased from 25 °C to 20 °C and the curing speed slowed down as well. The products with 4% low-acyl gellan gum had a denser gel network, which was harder than that with 4% κ-carrageenan. Gelatin weakened the hardness and elasticity, but greatly increased the adhesion. Conclusion: Appropriate low-acyl gellan gum and κ-carrageenan contributed to the molding and curing of starch, and the curing performance of κ-carrageenan was better than that of gellan gum, while gelatin had no auxiliary curing ability.