Review of recent applications and research progress in hybrid and combined microwave-assisted drying of food products: Quality properties

Abstract

The growing concerns over product quality have increased demand for high quality dried food products and encouraged researchers to explore and producers of such products to implement novel microwave (MW)-assisted drying methods. This paper presents a critical review of the key principles and drawbacks of MW-assisted drying as well as needs for future research. In this article, recent research into application of microwaves as an alternative heat source, applications and progress in hybrid MW-assisted drying that rely on various drying media and combined two or three stages of MW-assisted drying for the preservation of food products is reviewed critically. The effect of different MW-assisted drying methods, conditions and initial pretreatments on the thermophysical properties, color, nutritional value and rehydration potential of dried food products is discussed in detail along with the discussion on how the material properties evolve and change in structure, color, and composition during MW-assisted drying and recent attempts at mathematical modeling of these changes made for different fruits and vegetables. It should be noted that most of the published results were obtained in laboratory-scale dryers. Pilot-scale testing is needed to bridge the gap between laboratory research and industrial applications to fulfill the potential for novel hybrid and combined MW-assisted drying methods and to expand their role in food processing.

Keywords:

• Microwave-assisted drying
• thermophysical properties
• color
• nutritional value
• rehydration potential
• mathematical models

Additional information

Funding

This study was supported by the Polish National Science Center (grant No. 2015/17/B/NZ9/03601, title: The effect of unconventional pretreatment methods on the kinetic of hybrid dehydration and physical and chemical properties of cranberries Vaccinum macrocarpon) and the University of Warmia and Mazury in Olsztyn (Grant No. 16.610.001-300).