In order to investigate the effects of water activity and storage temperature on moisture content, and to explore the thermodynamic characteristics of net adsorption heat, enthalpy, entropy and free energy of dried ‘Chuliang’ longan. The static weighing method was used to determine equilibrium moisture content of dried ‘Chuliang’ longan at 20, 30, and 40 ℃ with a range of water activities from 0.113 to 0.946. The adsorption isotherms were plotted and the experimental results were fitted by 6 commonly-used agricultural products adsorption models. The results showed that the moisture adsorption isotherm of dried ‘Chuliang’ longan was type III and the Halsey model was most suitable for describing adsorption isotherm. In addition, the net adsorption heat decreased with the increase of moisture content and approached to zero as equilibrium moisture content was higher than 30%d.b. (dry basis). The net adsorption heat was equal to the enthalpy changes, which ranged from 0.2 kJ/mol to 467.69 kJ/mol. Changes of entropy values decreased with the increase of moisture content, while temperature showed no significant effect. The water adsorption process of dried ‘Chuliang’ longan could be explained by enthalpy-entropy complementarity theory, which was driven by enthalpy. The results provide a reference for the processing, packaging and safe storage of ‘Chuliang’ longan.
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