Akademik Veri Yönetim Sistemi
Journal of Food, Agriculture and Environment, cilt.11, ss.2803-2809, 2013 (SCI-Expanded)
Moisture adsorption characteristics of pastirma at different temperatures and water activities were investigated using the isopiestic method at 10°C, 20°C and 30°C over a water activity (aw) range of 0.2-0.9. The isotherms of the pastirma were exhibited Type II behavior with the sorption capacity decreased with increasing temperature. Equilibrium moisture content data were correlated by the different mathematical models that are usually applied to food stuff (Halsey, Peleg, Mod-BET, GAB and Harkins-Jura), that the best fit of the experimental data were obtained with the Peleg model in the range of temperatures and water activities investigated. Thermodynamic properties such as differential enthalpy and entropy, enthalpy-entropy compensation, spreading pressure, net integral enthalpy and entropy were determined from moisture adsorption isotherm data of pastirma. The experimental data were analyzed by a thermodynamic approach that the net isosteric heat and differential entropy were increased with decreasing moisture content and the spreading pressure was increased with increasing water activity, and decreased with increasing temperature. The spreading pressure was increased with increasing water activity, and decreased with increasing temperature. The net integral enthalpy was decreased with increasing moisture content. The integral entropy was increased with moisture content in the negative value. The enthalpy-entropy compensation theory was applied to water adsorption of pastirma. The adsorption process of pastirma was determined to be enthalpy-controlled.