Determination and prediction of thermal conductivity of frozen part baked bread during thawing and baking

The thermal conductivity of food is usually measured in isothermal conditions with a line-heat source probe. The thermal conductivity of bread during the baking phase is function of temperature and is an important parameter to assess. This work aims at (i) developing a measurement method of thermal conductivity in pseudo-non-isothermal conditions, usable during the part baked bread thawing–baking phase, and (ii) establishing models to predict the change of the thermal conductivity as function of the temperature. The line-heat source probe method has been used, the probe temperature being corrected by subtracting the temperature increase due to the baking. Values obtained in pseudo-non-isothermal conditions during the thawing–baking phase are similar to these ones obtained in isothermal conditions. A parallel model has been successfully used to fit the experimental values of the thermal conductivity of bread during the baking phase.