Thermal conductivity of tomato paste

Experimental measurements of the thermal conductivity and thermal diffusivity of tomato paste at concentrations of 27–44° Brix are reported. The thermal conductivity was measured in a guarded hot-plate apparatus while the diffusivity was estimated by a simplified transient method. The thermal conductivity (λ) values fell in the region of 0·460–0·660 W m^?1 K^?1, decreasing with increasing solids concentration and increasing as the temperature was raised from 30 to 50°C. The temperature effect was less pronounced at higher solids concentration. The thermal diffusivity of tomato paste at 35° Brix and 20°C was estimated as 1·42 × 10^?7 m² s^?1, which is in good agreement with data from the steady-state method.