Curdlan modulates potato starch gelatinization and gelation: Mechanisms of interaction, structural enhancement, and texture improvement in hydrogel foods

To address the poor processability and undesirable texture of low-concentration potato starch (PS) gels, we hypothesized that curdlan (CD) modulates these limitations through competitive water absorption and intermolecular interactions. This study systematically investigated PS/CD blend systems (5 wt%, ratios 100:0–70:30) using rapid visco analysis (RVA), differential scanning calorimetry (DSC), rheology, small-angle X-ray scattering (SAXS), low-field nuclear magnetic resonance (LF-NMR), and texture profiling. During heating, CD competed with PS for water, delaying gelatinization (T_c ↑4.02 ± 0.63 °C), reducing viscosity (peak viscosity ↓31.3 % at 95:5), and lowering gelatinization enthalpy (ΔH ↓37.8 %) by restricting amorphous hydration and facilitating crystalline domain disintegration. CD simultaneously attenuated shear-thinning behavior (n ↑38 %), enhancing processability. During cooling, CD accelerated network formation via hydrophobic associations and hydrogen bonding, increasing gel elasticity (G′ ↑336 % at 25 °C and 70:30) and fractal dimension (D ↑4.3 %). Optimal CD addition (95:5) yielded a denser dual-network structure with 50 % smaller pores and superior textural properties (hardness ↑21 %, chewiness ↑83 %). However, excessive CD (>20 %) inhibited network integrity due to increased molecular spacing. These findings demonstrate CD's dual role in inhibiting gelatinization yet accelerating gelation, providing a practical strategy to tailor the processability and texture of high-quality PS-based foods.