Constructing anisotropic and strong polysaccharide-based hydrogels with stretching-dehydration strategy: Effect of sodium alginate, pectin, gellan gum, and curdlan

Polysaccharide-based hydrogels are widely utilized in the food industry and materials science due to their safety and abundance from natural sources. However, their functionality is often limited by poor mechanical properties, primarily due to their simple and isotropic structures. In this study, the stretching-dehydration (SD) processing was applied to create anisotropic structure and enhance the mechanical properties in polysaccharide-based hydrogels, specifically sodium alginate (SA), pectin (PE), gellan gum (GG), and curdlan (CU). Among these, low molecular weight sodium alginate (SA-L) hydrogel exhibited notable stretching-induced anisotropy and structural stability during dehydration. Furthermore, increasing the controlled strains (CSN) could improve anisotropy, stretching strength, and Young's modulus which reached up to 100 MPa in anisotropic SA-L hydrogel. The anisotropic hydrogels closely mimicked the microstructure of whole-muscle foods. Sensory evaluations highlighted the enhanced chewiness and hardness, suggesting the anisotropic hydrogels are promising candidates for emulating whole-muscle textures. This work highlights the potential of anisotropic hydrogels produced through simple SD treatment as advanced materials for both food and biomimetic applications.