International E-publication: Publish Projects, Dissertation, Theses, Books, Souvenir, Conference Proceeding with ISBN.  International E-Bulletin: Information/News regarding: Academics and Research

Microwave Drying of Onion Slices

Author Affiliations

  • 1 Dept. of Processing and food Eng., College of Tech. and Eng., Maharana Pratap University of Agriculture and Technology, Udaipur, INDIA

Res.J.chem.sci., Volume 2, Issue (4), Pages 57-60, April,18 (2012)


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 m/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.


  1. Sagar V.R. Prepration of onion powder by means of osmotic dehydration and its packaging and storage. Journal of food science and technology, 38(5), 525-28 (2001)
  2. Krokida M.K. and D. Marinos-Kouris, Rehydration kinetics of dehydrated products, Journal of Food Engineering, 57, 1-7 (2003)
  3. Jayaraman K.S. and D.K. Das Gupta, Dehydration of fruit and vegetables-recent developments in principles and techniques, Drying Technology, 10, 1-50 (1992)
  4. Baroni A.F. and Hubinger M.D., Drying of onion: effects of pretreatment on moisture transport, Drying Technology, 16(9&10) (1998)
  5. Torreggiani D., Osmotic degydration in fruits and vegetable processing, Journal of Food Research International, 26, 59-68 (1993)
  6. Tulasidas T.N., Raghavan G.S.V., Majumdar A.S. and Akyel C., Quality and energy aspects in microwave drying of raisins, Presented at the ASAE meeting at Chicago Illinois, Paper No 95-3181 (1995)
  7. Schiffman R.F., Microwave and dielectric drying, In: Handbook of Industrial Drying, 2nd Edition, Vol. 1, Mujumdar A.S. (ed.), Dekker, New York (1995)
  8. Shivhare U.S., Raghavan G.S.V. and Bosisio R.G., Modelling the drying kinetics of maize in microwave environment, Journal of Agricultural Engineering, 57(3), 199-205 (1994)
  9. Tulasidas T.N., Combined convective and microwave drying of grapes, Ph.D., Thesis submitted to the faculty of graduate studies and research of McGill University, Macdonald campus, Canada H9X 3V9 (1994)
  10. Maskan A., Kaya S. and Maskan M., Hot air and sun drying of grape leather (pestil), Journal of Food Engineering, 54, 81–88 (2002)
  11. Doymaz I., Effect of pre-treatments using potassium metabisulphite and alkaline ethyl oleate on the drying kinetics of apricots, Biosystems Engineering 89, 281–87 (2004)
  12. Decareau R.V. and Peterson R.A., Microwave Processing and Engineering. Ellis Horwood, England (1986)