Effects of Curdlan on 3D-Printed Meat Analogs Based on Stropharia rugosoannulata Mycelium and Pea Protein Isolate: Printability, Rheology, and Texture

mycelium is a naturally fibrous and sustainable protein source for meat analogs; however, its weak gel-forming ability and poor extrudability limit its printability and structural stability. In this study, extrusion-based 3D-printable composite inks were developed using mechanically fragmented mycelium, pea protein isolate (PPI), and curdlan (CUR). The effects of mycelium and CUR concentrations on printability, rheological properties, water-holding capacity, water distribution, thermal properties, and texture were systematically evaluated. The results showed that mechanical fragmentation for 20 s effectively dispersed the mycelial aggregates while preserving the filamentous network. CUR markedly improved extrusion continuity, print accuracy, and shape fidelity after deposition. All inks exhibited shear-thinning behavior. Increasing CUR concentration enhanced apparent viscosity, storage modulus, thixotropic recovery, water-holding capacity, and thermal stability, while converting part of the immobilized water into bound water within the gel network. In addition, CUR strengthened hydrogen bonding in the composite inks. Texture profile analysis of heated meat analogs showed that hardness, springiness, cohesiveness, gumminess, chewiness, and resilience increased progressively with increasing CUR concentration. Among the tested formulations, the ink containing 50% mycelium, 5% PPI, and 6% CUR exhibited the best balance between printability, structural stability, and meat-like texture, showing the closest textural similarity to boiled chicken breast. These findings provide a practical strategy for fabricating mycelium-based meat analogs with improved printability and meat-like texture.