Rheological Characterization of Yeast Protein–Sanxan Composite Hydrogels via SAOS, LAOS and Thermal Analysis

Future foods are driving an urgent need for sustainable and functional protein resources, and synthetic biology is emerging as a powerful platform to produce such proteins efficiently. Here, we designed a yeast protein (YP)–sanxan composite hydrogel obtained. The introduction of YP significantly improved thermal stability (by 5–15 °C) and ensured polymer compatibility. Rheological analysis indicated a frequency-dependent weak gel (tan δ = 0.1–0.3), making it suitable for safe swallowing. The material exhibited Type III nonlinear viscoelastic behavior, characterized by inter-cycle strain softening and a weak overshoot in G″, with Lissajous curves revealing a strain-induced transition from solid-like to fluid-like behavior. Crucially, YP-reinforced gels (5–20%) exhibited higher elastic moduli, indicating that the incorporation of YP strengthened the gel network and increased its structural rigidity, as further confirmed by Strain Sweep. With its tunable rheology and superior thermal stability, this hydrogel holds great potential for functional foods, 3D food printing, delivery systems, and biomedical scaffolds.