Drying of tomato by using different drying techniques

Drying which is a practice used to keep agricultural products safely has been carried out since early ages. The purpose of drying process is getting rid of free water so that in biochemical reactions and microorganism activities can be stopped. In this study, three different drying techniques were applied to tomato. These methods are tray drying, Infrared drying and Spray drying. The experimental results indicated that drying rate decreases both increasing with drying time and decreasing moisture content. To select the best thin-layer drying models for the drying treatments, 5 mathematical models were fitted to the experimental data. The model that best fits the drying data has been found to be Modified Page Equation. Lycopene, β-carotene and ascorbic acid value of dried and fresh tomatoes were determined by HPLC method. Ascorbic acid content of fresh tomatoes was 493.49 mg/100 g dry matter. Drying at 60 oC and at an air velocity of 1.5 m/s decreased amount of ascorbic acid content of tomatoes by about 58.71. In experiments using a tray dryer, it was observed that lycopene and β-carotene losses increased as the drying temperature increased.