Pineapple of cv Extra Sweet (Costa Rica), peeled and cored by a spoon soil auger (d = 25mm), was mechanically cut into 6.0 mm thick rings. Pineapple rings were either soaked in pineapple juice or sucrose solution (both at 50% w/w) for 30 minutes at 20°C and at atmospheric pressure. The ratio fruit/solution was 1/3. Not pre-treated and pre-osmodehydrated rings were air dehydrated at 70-75-80 °C (dry bulb) up to a constant weight. Air dehydration was performed using an alternate upward-downward air-circulated pilot drier (Thermo-Lab. Codogno, LO) operating at an air velocity of 1.5 m/s. Each trial was repeated twice. The samples that were not immediately analysed were sealed in a high barrier film bag and stored at room temperature in glass jars containing anhydrous calcium chloride.