Thermal diffusivity of soursop (Annona muricata L.) pulp

The thermal diffusivity (alpha) of soursop pulp was evaluated by the use of heat penetration curves in 8Z short cans which were considered as finite cylindrical objects. The pulp was obtained from fruits belonging to the same lot and tested at two different maturity levels (ripe and unripe). The experiments were carried out at three different temperature ranges including freezing ones. The results showed that the thermal diffusivity had values sixteen-times lower at temperatures below 0 degrees C (1-1.53 x 10(-8) m(2)/s). The values for alpha at temperatures above 0 degrees C are in agreement with the results published by other authors for other vegetable products. There is no difference in the alpha values for the pulps from ripe and unripe fruits at a level of significance of 5%. (C) 2000 Published by Elsevier Science Ltd.