Moisture sorption isotherms of chitosan-glycerol films: Thermodynamic properties and microstructure

ABSTRACT Knowledge on the water sorption within agricultural products is extremely important for decision making during post-harvest procedures. In order to improve this knowledge, thermodynamic properties regarding water sorption provide useful data. Thermodynamic properties of castor beans, related to sorption, were determined. Static gravimetric technique under different conditions of temperature (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled humidity environment. After the sorption procedure, differential enthalpy, differential entropy and Gibbs free energy of this process were calculated and decreased with increased values of equilibrium moisture content.

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Effect of drying methods on the moisture sorption isotherms and thermodynamic properties of mint leaves

Journal of Food Science and Technology ◽

10.1007/s13197-011-0302-7 ◽

2011 ◽

Vol 49 (4) ◽

pp. 439-449 ◽

Cited By ~ 22

Author(s):

Ali Coşkun Dalgıç ◽

Hatice Pekmez ◽

Kadir Bülent Belibağlı

Keyword(s):

Thermodynamic Properties ◽

Sorption Isotherms ◽

Moisture Sorption ◽

Drying Methods ◽

Moisture Sorption Isotherms

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Moisture sorption isotherms of sunflower seeds: Thermodynamic analysis

Ciência e Agrotecnologia ◽

10.1590/1413-7054201943011619 ◽

2019 ◽

Vol 43 ◽

Cited By ~ 2

Author(s):

Renata Cássia Campos ◽

Paulo César Correa ◽

Iasmine Ramos Zaidan ◽

Úrsula Ramos Zaidan ◽

Rildo Araújo Leite

Keyword(s):

Thermodynamic Properties ◽

Water Content ◽

Sorption Isotherms ◽

Moisture Sorption ◽

Sorption Process ◽

Initial Water Content ◽

Sunflower Seeds ◽

Initial Water ◽

Desorption Process ◽

Moisture Sorption Isotherms

ABSTRACT The study of the thermodynamic properties provides the knowledge of the sorbent affinity by the water and the spontaneity of the sorption process, important to design drying equipment and to predict hygroscopic behavior during storage. This work aimed to determine and evaluate isotherms of hygroscopic equilibrium and thermodynamic properties for different equilibrium conditions (water contents and temperatures) in sunflower seeds, using the indirect static method. Sunflower seeds with initial water content of 0.164 (decimal, dry basis - d.b.) were used. Fifteen mathematical models were tested for hygroscopic equilibrium modeling, and the Smith model presented the best fit. It was verified that the thermodynamic properties were influenced by the water content, the integral isosteric desorption heat increased with the decrease of the equilibrium water content, ranging from 1.787 to 2.670 kJ kg-1 to 0.198 to 0.0518 (decimal, d.b.), respectively, the desorption process of the sunflower seeds was controlled by the enthalpy and the Gibbs free energy, which varied from 3.6363 to 200.1730 kJ kg-1, was positive for the temperatures studied, with increase to during the desorption process, proving to be a non-spontaneous process.

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