FOOD AND BIOPROCESS TECHNOLOGY, vol.8, no.3, pp.516-525, 2015 (SCI-Expanded)
This study was performed to determine the drying characteristics and final product quality of tomato slices dried at infrared radiation intensities of 1830, 2385, 2640, 2880, and 3165 W/m(2) and at air velocities of 1.0, 1.5, and 2.0 m/s. A comprehensive analysis of dried products was performed on their drying kinetics, drying time, specific energy consumption, shrinkage, rehydration ratio, color, vitamin C, and lycopene. The results showed that drying time was prolonged with increasing air velocity while it was shortened with increasing infrared radiation intensity. The lowest energy consumption occurred at the air velocity of 1.0 m/s and at infrared radiation intensity of 2640 W/m(2). Shrinkage and rehydration ratio varied between 0.139 from 0.203 and 2.14 from 3.40 for all the drying conditions, respectively. Delta E values varied from 5.70 to 13.06. The contents of vitamin C and beta-carotene in infrared dried tomatoes were decreased by 2-51 and 5-51 %, respectively, while there was a significant increase in lycopene content varying between 50 from 529 %. Totally, it was observed that infrared drying of tomato provided good nutrient retention and low cost of energy. Therefore, infrared radiation can be suggested in both nutritional and operational aspects in terms of drying tomato slices.