Upgrading quality of dried tomato: Effects of drying methods, conditions and pre‐drying treatments

Rate of moisture removal increased with temperature in tomato (Lycopersicon esculentum Mill) pieces dried, using through‐flow and cross‐ flow air patterns, in a pilot‐scale cabinet dryer at 60, 70 and 80°C with an air velocity of 1.75 ms−1. Moisture removal was faster for through‐flow than for cross‐flow drying at each temperature. Lower moisture content and improved appearance were achieved by dipping, for 3 min, tomato slices in NaCl (300 g litre−1) or in a solution containing 9 g litre−1 potassium metabisulphite and 100 g litre−1 NaCl, or by adding NaCl (33 g kg−1) to tomato slurry prior to sun or oven drying. Nigerian‐type sauces made from pretreated oven‐dried tomatoes were considered acceptable, though inferior to that made from drum‐dried tomatoes.