Enthalpy-entropy compensation based on isotherms of mango

Author(s)

Javier Telis-Romero ^[1] ; Márcio N. Kohayakawa ^[2] ; Vivaldo Silveira Jr ^[3] ; Maria A. M. Pedro ^[4] ; Ana L. Gabas ^[5]

Affiliation

^[1] Universidade Estadual Paulista. Depto. de Engenharia e Tecnologia de Alimentos

^[2] Universidade Estadual de Campinas. Depto. de Engenharia de Alimentos

^[3] Universidade Estadual de Campinas. Depto. de Engenharia de Alimentos

^[4] Universidade Estadual Paulista. Depto. de Engenharia e Tecnologia de Alimentos

^[5] Universidade de São Paulo. Depto. de Engenharia de Alimentos

• Document type: Journal article
• Source: FOOD SCIENCE AND TECHNOLOGY; v. 25, n. 2, p. 297-303, 2005-06-00.

Abstract

Moisture equilibrium data of mango pulp were determined using the static gravimetric method. Adsorption and desorption isotherms were obtained in the range of 30-70 ºC, to water activities (a w) from 0.02 to 0.97. The application of the GAB model to the experimental results, using direct nonlinear regression analysis, provided agreement between experimental and calculated values. The net isosteric heat of sorption was estimated from equilibrium sorption data, using the Clausius-Clapeyron equation. Isosteric heats of sorption were found to increase with increasing temperature and could be well adjusted by an exponential relationship. The enthalpy-entropy compensation theory was applied to sorption isotherms and plots of deltaH versus deltaS provided the isokinetic temperatures, indicating an enthalpy controlled sorption process. (AU)