Modeling drying kinetics of grape seeds and skins from Turkish cultivars

Gezer, Pervin Gizem
Grape pomace is a valuable waste product and various end-products have been obtained after treatments. Recently, these have been commercialized due to their health-promoting effects. Drying is a crucial part of these treatments. This study aimed to analyze the drying kinetics of grape pomace parts, which are seeds and skins. Two grape types were used in this study, namely Emir and Bogazkere varieties of Vitis Vinifera species. Seeds and skins of each variety were dried in a tray dryer at an air velocity of 1 m/s with four different air temperatures; 40, 50, 55 and 60°C. The drying curves showed that the drying r ate increased with the air temperature. Six different drying models were selected from the literature and the best fitted model was determined by application of appropriate statistical methods. It was found that for Bogazkere seeds; Modified Two Term Model, for Bogazkere and Emir skins; Modified Page Model and for Emir skins; Logarithmic Model gave the best fit. The effective moisture diffusivities of each type were found for each temperature and were determined by two different approaches, experimental and estimation. The values and variation of Deff / L2 with temperature were calculated and were found to be increasing with temperature and that the Deff / L2 values were larger for grape skins than grape seeds. Arrhenius type equation was used in order to explain the temperature dependency of Deff / L2.
Citation Formats
P. G. Gezer, “Modeling drying kinetics of grape seeds and skins from Turkish cultivars,” M.S. - Master of Science, Middle East Technical University, 2011.