THERMAL-PROPERTIES OF TROPICAL FRUITS AND VEGETABLES

The thermal diffusivity, alpha, and thermal conductivity, k, of a wide variety of tropical vegetables and some fruits were determined using a mathematical model previously proposed and tested. In this mathemati cal model it was assumed that the thermal properties were not a functi on of the temperature. The vegetables and fruits studies were: potato (Solanum tuberosum), carrot (Daucus carota), sweet-potato (Ipomoea bat atas), yucca (Manihot dulcis), sugar beet (Beta vulgaris), yam (Discor ea alata), ocumo (Xanthosoma sagitti folium), celery (Arracacia xantho rhiza), orange (Citrus aurantium) and grapefruit (Citrus paradisi) wit h and without peel. In addition, the heat capacity, density and water content of these fruits and vegetables were also measured. Thermal con ductivity values were between 0.60 and 0.75 W/m.K. Heat capacity value s oscillated between 3.3 and 4.2 kJ/kg.K. The products had density val ues between 1 031 and 1323 kg/m3. The minimum water content was 55% an d the maximum was 90%. The repeatability of the results and the simpli city of the experimental equipment make this method a good alternative to determine thermal properties of foods.