Cassava starch enhances the printability and swallowability of rapeseed protein gels for 3D-printed dysphagia foods.

Plant-based proteins have attracted increasing attention in the development of easy-to-swallow foods and three-dimensional printing (3DP) materials due to their excellent nutritional properties. However, the disordered arrangement of protein molecular chains in rapeseed protein (RP) results in insufficient structural stability and poor self-supporting capacity during 3DP, leading to collapse behaviour. To address this limitation, cassava starch (CS) was incorporated into RP gels at different CS: RP ratios to improve printability and swallowing properties. FT-IR and XRD analyses demonstrated that the addition of 1%-5% CS promoted hydrogen bonding interactions with RP, thereby enhancing the gel network structure and increasing the storage modulus. Texture analysis revealed that the obtained gels possessed suitable cohesiveness and hardness (28.67-36.33 g), indicating favorable swallowability characteristics. Moreover, the incorporation of CS significantly improved the viscosity, printing fidelity, and self-supporting strength of RP gels, effectively eliminating collapse during the printing process. Among all formulations, the 2%-CS group exhibited the optimal printing performance, achieving the highest storage modulus, the lowest creep strain (3.06%), and a printing accuracy of 97.37%. In addition, this formulation satisfied the requirements for Level 4 foods according to the International Dysphagia Diet Standardisation Initiative (IDDSI). LF-NMR analysis further indicated that the enhanced properties originated from the water-retaining network formed through cross-linking interactions between RP and CS. Overall, low concentrations of CS effectively improved the printability and swallowability of RP gels, providing a scientific basis for the development of 3D-printed dysphagia-friendly foods.