Microwave Drying of Onion Slices

White onion slices were dried using microwave drying technique. The effect of process parameters during microwave dehydration such as effect of various power levels (0.25, 1.00, 1.50 and 2.25 kW) on mass reduction, water loss and diffusivity were studied. It was found that the mass reduction and water loss increased with increase of power level. The moisture diffusivity varied in the range of 6.491 × 10 -09 to 6.491 ×10 -08 m²/s. The drying times of onions slices by microwave drying at 0.25, 1.00, 1.50 and 2.25 kW level were 15.86, 6.78, 5.3 and 3.2 hrs. Quality of dried product in respect to colour, rehydration and water activity was superior.