Drying experiments were performed in a laboratory scale microwave-convective dryer available in the Division of Post Harvest Technology, Indian Agricultural Research Institute, New Delhi. The microwave oven (WP700L17.3 MW Oven, LG make, 17 L Capacity) with technical features of ~230 V, 50 Hz, and 700 W with a frequency of 2450 MHz has the dimensions of 295, 458 and 370 mm and consisted of a turn table of 270 mm diameter at the base of the oven. The combined microwave-hot air drying experiments were thus conducted with continuous microwave power of 280 W and step down intervals of 70 W, in conjunction with hot air at 30, 45 and 60°C temperatures at constant air velocity of 1.5 m/s.
200 g of osmotically dehydrated yellow sweet pepper was arranged in a single layer on the rotating glass plate and placed in the centre of the oven and the drying process was started for different combinations of microwave power and air temperature. Drying process continued until the moisture content of samples fell down to about 6 % (w. b). All weighing processes were completed in