Drying and characterization of grape posa (cibrer) using different dryers

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. In this study, grape pulp obtained from Elazığ region was dried and drying kinetics were determined and modeled. In addition, fatty acids and water soluble and fat soluble vitamins were analyzed for characterization of pulp and seeds. Grape pulp of each variety were dried in a tray dryer at an air velocity of 1.5, 2.0 and 2.5 m/s with three different air temperatures; 35, 45 and 55°C. The drying curves showed that the drying rate 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. Modified Page model was found to be the most suitable for dried grape pulp. Fatty acids were analyzed in grape pomace and grape seeds and the data were obtained in accordance with the literature. The most common oil in grape pomace is palmitic acid with 35.66% and linoleic acid with 59.12% in grape seeds Keywords: Drying, grape seed, grape skin, modeling, effective moisture diffusivity