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Keywords:

  • high pressure;
  • freezing;
  • vegetable microstructure

ABSTRACT:

A histological technique was used to evaluate modifications on the microstructure of peach and mango due to classical methods of freezing and those produced by high-pressure-shift freezing (HPSF). With the high-pressure-shift method, samples are cooled under pressure (200 MPa) to -20°C without ice formation, then pressure is released to atmospheric pressure (0.1 MPa). The high level of supercooling (approximately 20°C) leads to uniform and rapid ice nucleation throughout the volume of the specimen. This method maintained the original tissue structure to a great extent. Since problems associated with thermal gradients are minimized, high-pressure-shift freezing prevented quality losses due to freeze-cracking or large ice crystal presence.