Rehydration of Dried Wheat Noodles with Different Gluten Contents at Various Temperatures

The rehydration process of dried wheat flour noodles (flat noodles) prepared by adding 0, 5, 10, and 15% wheat gluten by weight to wheat flour was measured at temperatures ranging from 40 to 80°C. Regardless of the gluten content, the rehydration process at any temperature was well described by an empirical hyperbolic equation regarding the rehydration time. The equilibrium moisture content and initial rehydration rate were smaller for the noodles with higher gluten content. The temperature dependence of equilibrium moisture content varied significantly between 50 and 60°C at any gluten content, reflecting the gelatinization temperature of the starch in the flour, and could be expressed by the van’t Hoff equation for the high-temperature region. The change in rehydration enthalpy at high temperatures was almost independent of the gluten content of noodles. The temperature dependence of the initial rehydration rate could also be expressed by the Arrhenius equation over all temperature ranges tested, and the activation energy for rehydration was almost independent of the gluten content.