Kinetic and Thermodynamic Studies of Extraction Process for Soluble Sugars and Juice Yield from Sweet Sorghum

Abstract

In this study, the kinetic and thermodynamics study of solid-liquid extraction of sweet sorghum juice was carried out. Five kinetic models namely Patricelli, Peleg, log, power and Page’s models were tested in order to determine the one that best fits the recovery of soluble solids (RSS) and the juice yield data obtained at 35–65 ℃ and 0–100 minutes. The assessment of the performance of the models was achieved from statistical data such as , adjusted , root mean square error (RMSE), and percentage average absolute relative deviation (AARD) obtained by comparing the experimental data with the predicted date. The thermodynamic parameters determined were activation energy (), enthalpy change (), entropy change (), and free energy change (). The results showed that the RSS and juice yield increased with an increase in the temperature with the highest values achieved at 65 ℃. The extraction process was the fastest at the beginning until after 10 minutes when the effect of time became insignificant. Also, Patricelli’s model had the best performance while Page’s model had the worst performance. Finally, the extraction processes were endothermic (positive enthalpy change), reversible (negative entropy change), and not spontaneous but endergonic (positive free energy change). The determination of these kinetic and thermodynamic parameters will help in understanding the extraction mechanisms, scaling up and designing the extraction process, and improving energy efficiency.