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.