Multi-network crosslinked plant-based hydrogels with enhanced mechanical performance for 3D-printed edible cartilage...

Biomimicking plant-based cartilage structures is essential for improving the texture of plant-based meat. This study developed a triple-crosslinked hydrogel using soy protein isolate (SPI), sodium alginate (SA), and curdlan (Cur) via transglutaminase (TGase) covalent crosslinking, Ca²⁺ ionic crosslinking, and Cur thermal gelation. The optimized formulation (20 % SPI + 0.5 % SA + 2 % Cur) exhibited excellent rheological properties and 3D printing for precise fabrication of stable 3D structures. In this system, TGase catalyzed the formation of a flexible and stable covalent network, SA and Ca²⁺ created a rigid ionic network for energy dissipation, and Cur formed triple helices upon heating, improving mechanical strength through hydrophobic interactions. SEM revealed a denser and more ordered microstructure compared to single-crosslinked hydrogels, supporting the synergistic reinforcement. These networks improved mechanical strength, texture, water retention, and freeze-thaw (FT) stability. The triple-crosslinked hydrogel showed significantly higher compressive modulus (339.7 ± 24.5 kPa), toughness (78.92 ± 4.24 mJ), hardness (60.8 ± 0.5 N), and chewiness (100 ± 7.2 mJ), closely resembling the structure and texture of chicken cartilage. This work provides a novel strategy combining multi-network crosslinking and 3D printing to develop functional cartilage analogues, offering theoretical and practical support for the design of plant-based connective tissues.