INVESTIGATION OF EFFECTS OF VARIOUS DRYING METHODS ON THE QUALITY CHARACTERISTICS OF APPLE SLICES AND ENERGY EFFICIENCY

WOS: 000353855200016In this study, the effects of tray drying, heat-pump drying, freeze drying, and microwave drying methods on the quality characteristics of apple slices were investigated and energy efficiencies of drying methods were determined. Drying time of samples were calculated as 50 min, 90 min, 270 min, and 20 min for tray, heat-pump, freeze, and microwave drying respectively. Quality characteristics of apple slices were determined by physical (moisture content, color values, water activity, rehydration, bulk density), chemical (total phenolic, total and invert sugar, pectin) and sensory analysis. Energy efficiencies of drying methods were evaluated by calculating the Specific Moisture Extraction Rate (SMER), Moisture Extraction Rate (MER), Specific Energy Consumption (SEC), energy consumption, and energy cost. Considering the quality characteristics of the products, the results showed that dried apple slices which were produced by using microwave and freeze drying methods had a better quality comparing to the tray and heat-pump drying methods. On the other hand, the lowest energy consumption and the highest SMER and MER values were obtained from the heat-pump dryer. According to the purpose of the production obtained quality and cost values will help us in selecting the dryer