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Desorption isotherms and thermodynamic properties of sweet corn cultivars ( Zea mays L.)
Author(s) -
De Oliveira Gabriel Henrique Horta,
Corrêa Paulo Cesar,
Araújo Eduardo Fontes,
Valente Domingos Sárvio Magalhães,
Botelho Fernando Mendes
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2009.02163.x
Subject(s) - desorption , thermodynamics , equilibrium moisture content , relative humidity , arrhenius equation , gibbs free energy , humidity , chemistry , enthalpy , activation energy , adsorption , physics , sorption
Summary The desorption isotherms and thermodynamic properties of two cultivars of sweet corn were obtained during the drying process of these products. The isotherms were determined by a dynamic method for various temperature and humidity conditions. Equilibrium moisture content ( X eq ) data were correlated by the Guggenheim–Anderson–de Boer model and an artificial neural network (ANN) model. These models were fitted to the experimental data. The X eq for corn grain increased with an increase in the relative humidity at fixed temperature and decreased with an increase in temperature at a constant relative humidity. The experimental data were analysed by a thermodynamic approach to obtain the isosteric heat of desorption (Δ H ), differential entropy (Δ S ), activation energy ( E a ) and Gibbs free energy (Δ G ). The Δ H and Δ S increased with a decrease in moisture content, while Δ G decreased exponentially with an increase in X eq . The Arrhenius equation was used to obtain E a values, with Supersweet corn having higher E a .