Printing characteristics and microwave infrared-induced 4D printing of chestnut powder composite paste

Chestnut flour is a material with unique properties but difficult to use in 3D printing. This work achieved 3D printing using sodium alginate (SA) and chestnut flour, and 4D printing of chestnut flour under microwave and infrared heating conditions. SA increased the modulus, viscosity, and hardness of the bioinks, but weakened starch gel structure. The puffing effect during microwave heating led to directional deformation of the 3D printed products, and the 1.0% SA content contributed to a more desirable deformation. Infrared heating for 4 min followed by microwave heating for 4 min (4IR4MW) reduced deformation and avoided collapse. Microwave and infrared heating would contribute to the flavor, texture and swallowability. This research created 4D printed chestnut flour food products with personalized and rapidly shape-changing behavior, providing a new technology for 4D food manufacturing.