[01] Sana Ben Mariem, Higher Institute of Agronomic Sciences of Chott-Mariem, University of Sousse, Sousse, Tunisia; Labratory of Thermal Process, Research and Technology Centre of Energy, Borj Cédria, Tunisia. [02] Salah Ben Mabrouk, Labratory of Thermal Process, Research and Technology Centre of Energy, Borj Cédria, Tunisia.

The adsorption and desorption isotherms of tomato were determined by static gravimetric method at different temperatures, in the range from 30°C to 60°C and relative humidities of 5%–85%. The curves obtained can be considered as type II according to the Brunauer–Emmett–Teller classification. Equilibrium moisture content data were correlated by different mathematical models usually applied to foodstuffs (GAB, Peleg, Smith, Caurie, Oswin…). A non-linear least square regression analysis was used to evaluate the models constants. The best fit of the experimental data was obtained with GAB and Peleg models. The Chung-Pfost model was the least adequate. Hysteresis was also observed at all temperatures investigated. The isosteric heat of sorption was determined using the Claussius–Clapeyron equation, and it decreases with increasing moisture content at the average temperatures investigated.

Equilibrium Moisture Content, Isosteric Heat, Sorption Isotherm, Tomato, Water Activity

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