A DEVELOPED INFRARED DRYER FOR DRYING AND STERILIZATION HIGH QUALITY TOMATO SLICES

The present study was implemented to assess the utilization of infrared radiation for drying tomato slices using a developed infrared dryer. The experimental parameters included different levels of infrared intensity (0.973, 1.093, and 1.161 kW/m2), inlet air temperature (40, 50 and 60 0C) and tomato slices thicknesses (3, 5 and 7mm). Two different drying models, simple exponential model (Lewis's) and the modified exponential model (Henderson and Pabis's) were used for describing the drying behavior and predicting the changes in moisture content of tomato slices during the drying process. Dried tomato slices quality was measured in terms of ascorbic acid and total phenolic content. The findings illustrated that the drying rate of tomato slices increased as the radiation intensity and drying air temperature increased, whilst it was decreased as slices thickness decreased. Both investigated models could describe the drying behavior of tomato slices satisfactory. The tomato samples dried at radiation intensity of 0.973 kW/m2 under air temperature of 50 0C and slices thickness of 5 mm with the use of the developed infrared dryer gave the highest quality of the dried samples in terms of ascorbic acid and total phenolic contents.