Curdlan-induced rheological, thermal and structural property changes of wheat dough components during heat treatment

To clarify the interactions among curdlan, starch and gluten, curdlan-induced rheological, thermal and structural properties of wheat dough during heating were investigated. When heating temperature exceeded 60 °C, 0.6% curdlan increased the stiffness of dough with a maximum storage and loss modulus. For starch, the increase of curdlan (0–0.9%) inhibited its gelatinization, and the peak and breakdown viscosity decreased by 28.1% and 24.5%, respectively, accentuating the dough strength. Regarding gluten, excessive curdlan (0.9%) delayed the thermal denaturation and increased the content of exposed sulfhydryl group (0.64 mmol/g for control dough vs. 0.83 mmol/g for treated dough, P < 0.05), resulting in the structural weakening of dough. Hydrogen bonds and hydrophobic interaction were involved in curdlan-gluten interactions at more than 75 °C. Some random coils of gluten were transformed into α-helix structure, which reduced the flexibility of the polypeptide chains. The microstructure confirmed the results of rheological properties that the dough containing 0.6% curdlan was more stable and denser (≥75 °C). In summary, during heating (>60 °C), the dough containing 0.6% curdlan was the most desirable with respect to viscoelasticity and strength, suggesting that it is possible to use curdlan to improve the processing characteristics of wheat dough.