Compression of Foods during Freeze-Drying: Water Plasticization at the Ice-Dry Layer Interface

  • C. Emami
  • J. M. Flink
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 302)

Abstract

The compressive mechanical properties of freeze-dried green beans show a pronounced decrease in rigidity when moisture content and/or temperature are increased. There exist several temperature and moisture combinations which give common values for mechanical properties. These combinations also give a common compressive behavior. Using this information on mechanical properties, it is possible to predict a stress-strain relationship, if given either a temperature, a moisture content, or the value of a pertinent mechanical property.

It is shown that the moisture contents and temperatures that exist in the dry layer during freeze-drying result in mechanical properties that are suitable for compression of the dry layer. From studies on compression behavior during freeze-drying, it is shown that applied compressive pressure is the main determinant of final degree of compression. Increasing the compressive pressure gave a higher compression effect and gave a more rapid drying, presumably due to improved heat transfer in the compressed dry layer.

From the above information, a simple method to predict compression behavior during freeze-drying was developed.

Keywords

Compressive Pressure Compression Behavior Tangent Modulus Green Bean Instron Test Machine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1991

Authors and Affiliations

  • C. Emami
    • 1
  • J. M. Flink
    • 2
  1. 1.Dunkin’ DonutBraintreeUSA
  2. 2.Novo Food Diagnostics A/SFrederiksbergDenmark

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