The Optimization of the Dehydration Temperature of Peels from Prickly Pears

The optimization of the prickly pear peel (PPP) dehydration temperature was addressed. Two indicators of efficiency were used to select the optimal dehydration temperature: one related to the process productivity, another to the energy consumption. To calculate them the PPP dehydration kinetics were measured at three different temperatures (i.e., 50, 60, and 70 °C) along with the energy consumption of the process. A mathematical model was used to fit the dehydration kinetics. The influence of the temperature on the kinetics was assessed by analyzing the dependence of the fitting parameters on the dehydration temperature. It was found that both the kinetic parameters and the equilibrium parameter depend on the temperature through an exponential-type equation. The model was also used to calculate both the process productivity and the average energy consumed by the dehydration cabinet per grams of evaporated water when 99% dehydration is reached. The two efficiency indicators suggested that the optimal drying temperature is 70 °C, both being the indicators decreasing function of the temperature.