Simultaneous determination of thermal conductivity and thermal diffusivity of food and agricultural materials using a transient plane-source method

Thermal conductivity (K) and thermal diffusivity (α) are two important physical properties essential for designing any food engineering processes. Recently a new transient plane-source method was developed to measure K and α in a variety of materials, but its application in foods has not been documented. Therefore, the objective of this work was to evaluate the feasibility of using this method for measuring K and α of foods. A calibrated probe, constructed with a resistance temperature detector (RTD), was used to simultaneously measure K and α of foods and other materials. For standard materials, such as water, mineral oil, ethanol, ethylene glycol, and olive oil, the measured K and α values of these materials were generally within 0.5–10% from the standard values in the literature. For food materials such as beef, chicken, flour, and apple, the measured values were within 0.2–15% of the K and α values of the same material reported in the literature. The results of this study suggest that the transient plane-source method is an accurate method for simultaneously measuring thermal conductivity and thermal diffusivity of foods.