3D-printed rice cake for dysphagia diet: Effect of rice flour/κ-carrageenan/curdlan complex gel on structure, swallowability, and storage

Rice cakes are a traditional rice-based dessert consumed in Asian countries. They are an excellent source of carbohydrates and can be used as a staple food. However, they have a hard and gummy texture. This study aims to create dysphagia-friendly rice cakes by adding κ-carrageenan (KC) and curdlan (CD) to rice flour. Samples with various KC:CD ratios (1:1, 2:1, 3:1, and 4:1) were compared to commercial rice cakes. XRD showed typical A crystal structures that were unaffected by the complex gel. FTIR spectra indicated hydrogen bond interactions enhancing gel strength. Viscosity analysis revealed shear-thinning behavior for samples with KC:CD ratios of 1:1 and 2:1 suitable for bolus rheology. Optimized printing conditions yielded structurally stable 3D-printed rice cakes meeting the international standard for dysphagia (IDDSI levels 5 and 6). Compared to commercial rice cakes, the experimental samples exhibited lower syneresis and delayed retrogradation, suggesting improved storage stability. Complex gel incorporation offers a method for controlling structural property, swallowability, and storage stability, potentially enabling dysphagia-friendly rice cake manufacturing via 3D printing.