Thermal Conductivity of Wheat Dough Determined by an Inversion Method within Freezing Temperature

The specific heats of three doughs with different moisture contents were measured using differential scanning calorimetry(DSC)in order to determine the thermal conductivity of wheat dough within the freezing temperature. Their thermal conductivity within the temperature range of -30℃ to 30℃ was derived using an inverse optimization in the COMSOL software. The results showed that the thermal conductivity increased gradually when the moisture content of the dough increased from 38% to 44%. With the decrease of temperature,the thermal conductivity of the dough gradually decreased. However,the thermal conductivity of doughs rose sharply when the dough temperature dropped just beyond the freezing points,and then slowly increased. Through further analysis of the relationship between thermal conductivity and moisture content of dough,a mathematical model was established for predicting the thermal conductivity of a dough from its temperature and moisture content in the range of quick freezing temperature.