The net isosteric heat of sorption or enthalpy of sorption is defined as the difference between the total heat of sorption and the heat of vaporization of pure water:
(4)
The net isosteric heat of adsorption and desorption for a given Xe was calculated using the Clausius-Claperyon equation:
(5)
wherein: DHb st is the enthalpy of sorption [k mol1];
Qb st is the total heat of sorption [kJ mol1];
R is the gas constant [8.314 J mol1 K1],
aw2 and aw1 are the values at absolute temperatures T2 and T1 [K],respectively; DvapHb is the heat of vaporization [kJ mol1].
The DHb st was calculated from the slope of ln(aw) versus (1/T) for a specific Xe.
Therefore, the application of this method requires the measurement of sorption isotherms at two or more temperatures(Yogendrarajah et al., 2015).
2.5.2. Thermophysical properties
The experimental behavior of physicochemical properties during drying process of banana slices was fitted to different correlations using Statgraphics Centurion v.15.0 (StatPoint®, Inc., USA), all correlation parameters were estimated by nonlinear regression.
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