9. Dehydration of Fruit and Vegetables in Tropical Regions

  1. Rajeev Bhat2,
  2. Abd Karim Alias2 and
  3. Gopinadhan Paliyath3
  1. Salim ur-Rehman and
  2. Javaid Aziz Awan

Published Online: 16 JAN 2012

DOI: 10.1002/9781119962045.ch9

Progress in Food Preservation

Progress in Food Preservation

How to Cite

ur-Rehman, S. and Awan, J. A. (2012) Dehydration of Fruit and Vegetables in Tropical Regions, in Progress in Food Preservation (eds R. Bhat, A. Karim Alias and G. Paliyath), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781119962045.ch9

Editor Information

  1. 2

    Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia

  2. 3

    Department of Plant Agriculture, University of Guelph, Guelph, Canada

Author Information

  1. National Institute of Food Science and Technology, University of Agriculture, Faisalabad, Pakistan

Publication History

  1. Published Online: 16 JAN 2012
  2. Published Print: 10 FEB 2012

ISBN Information

Print ISBN: 9780470655856

Online ISBN: 9781119962045



  • dehydration;
  • dehydro-freezing;
  • drum drier;
  • freeze drying;
  • forced draft;
  • natural draft;
  • sun drying;
  • solar drier;
  • tunnel drier


The introductory part of this chapter contains information on forms of water and its role in foods. Also merits and demerits of sun drying over dehydration will be discussed. Abundant sunshine in tropical areas can efficiently be utilized for sun drying of fruits and vegetables. In sun drying, moisture is removed by solar energy. The discussion about sun drying covers the areas of equipment, preparatory treatments, drying procedure, precautions, and post-drying care of the products. Moisture is also removed by artificial means with different dehydrators. In dehydration, drying atmosphere and factors affecting evaporation of water from food surface will be discussed. This section will include descriptions of various methods such as dehydration, freeze drying and dehydrofreezing. Types of dehydrators, including natural-draft, forced-draft, solar drier, tunnel driers, and conveyer driers, are discussed at length. Information on fluidized-bed driers for particulate or diced materials will be given. Spray driers, drum driers, special drying techniques (e.g., foam-mat drying) and use of latest techniques such as drying by application of energy from radiating microwave/ dielectric sources will also be covered. Evaporating moisture, thereby concentrating the soluble solids in foods, will be dealt with under evaporation/concentration. Binding of available moisture to produce intermediate-moisture foods could be a useful technique for tropical countries. At the end of the chapter the effect of drying on the nutritional value of dried foods will be discussed.