The objective of this work was to determine the desorption isotherms and thermodynamic properties of Allium sativum. These properties are indispensable, particularly in regard to garlic drying and storage in order to guarantee its quality prior to its industrial use as an important source of nutriment and meal for medicinal and cosmetic purposes. Desorption isotherms were determined using a static gravimetric method at four temperatures: 40°C, 50°C, 60°C and 70°C over a relative humidity range of 5-90%. All the curves exhibited type II behavior, according to Brunauer’s classification. Equilibrium moisture contents decreased as the temperature increased. The GAB model fitted well the desorption isotherm data for Allium sativum with the monolayer moisture content depending on the temperature. The Clausius-Clapeyron equation was used to evaluate the net isosteric heat of water desorption by using the GAB theoretical model in the studied temperature range. The net isosteric heat and the differential entropy decreased strongly as the moisture content increased respectively.
A. Touil, J. Litaiem, F. Zagrouba
Garlic, Sorption isotherms, Modelization, Enthalpy, Entropy