ABSTRACT
A method, built around a small glass encapsulated thermistor was used to measure the thermal conductivity and diffusivity of food materials. High temperature measurements were performed on tomato sauce and tomato paste. Thermal conductivity and thermal diffusivity were measured at 100, 130 and 150 °C and compared to literature values. In general, the values measured in this research were higher than those found in literature. The thermal property values (k, α) for tomato puree were in good agreement. Thermal conductivity of the tomato paste agreed quite well with the reported values. However, for the thermal diffusivity, the values were much larger than reported and variability between the different samples was substantial. This is thought to be caused by alterations in the tomato paste caused by prolonged heating at high temperatures. Measurements of thermal conductivity of liquid nutritional supplements at 95 and 150 °C were also performed. The results showed good replication and were consistent with values of water considering their composition.
