Design of multi-nozzle fixture and incorporation of various hydrocolloids to regulate 3D printing efficiency and anti-dysphagia properties of strawberry- pea protein isolate gels.

As the aging population continues to grow, an increasing number of individuals are suffering from dysphagia. 3D food printing enables the customization of food products regarding texture, nutrition, and appearance, making it an effective method for creating foods suitable for individuals with dysphagia. However, current 3D food printers face challenges in achieving large-scale production due to their slow printing speeds and low printing efficiency. In this study, hydrocolloids including gelatin (GL), xanthan gum (XG), and flaxseed gum (FG) were incorporated into the existing strawberry and pea protein isolate (PPI) gel and a multi-nozzle printer was designed, aiming to achieve highly efficient 3D food printing. Results showed that the incorporation of hydrocolloids enhanced the optimal printing speed from 20 mm/s to 50 mm/s, while the utilization of a multi-nozzle printer decreased the time required to produce a printing product from 610 s to 58 s. Moreover, there was no noticeable difference in appearance or size for the dual-nozzle and six-nozzle printing products. The hydrocolloids (GL and FG) enhanced the rheological properties and textural structure of the strawberry-PPI gels by increasing the bound water content, which improved the mechanical properties and 3D printing performance. The extruded filament surface of strawberry-PPI gels became smoother and the internal structure of the gels became denser with the incorporation of hydrocolloids. The results from the International Dysphagia Diet Standardization Initiative (IDDSI) indicated that the 3D printed products met the requirements for level-4 dysphagia foods. It can be concluded that both the incorporation of hydrocolloids and the development of multi-nozzle fixtures can enhance printing speed and facilitate large-scale production, offering valuable insights for the future of efficient 3D food printing.