Preservation of Microstructure in Peach and Mango during High-pressure-shift Freezing

Authors

  • L. Otero,

    1. Authors Otero and Sanz are with the Instituto del Frío, CSIC-Ciudad Universitaria, 28040 Madrid, Spain.
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  • M. Martino,

    1. Authors Martino and Zaritzky are with the Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CONICET, Facultad de Cs. Exactas and Facultad de Ingeniería, Universidad Nacional de La Plata-Calle 47 y 116 (1900) La Plata, Argentina.
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  • N. Zaritzky,

    1. Authors Martino and Zaritzky are with the Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CONICET, Facultad de Cs. Exactas and Facultad de Ingeniería, Universidad Nacional de La Plata-Calle 47 y 116 (1900) La Plata, Argentina.
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  • M. Solas,

    1. Author Solas is with the Departamento de Biología Celular, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain.
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  • P.D. Sanz

    Corresponding author
    1. Authors Otero and Sanz are with the Instituto del Frío, CSIC-Ciudad Universitaria, 28040 Madrid, Spain.
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  • This research was supported by the Comision Interministerial de Ciencia y Tecnología SGPN I+D (Spain) under project ALI97-0759. The authors also acknowledge the financial assistance provided by the Convenio de Cooperación Argentino-Español, CONICET - CSIC, Argentine - Spain.

Direct correspondence to P.D. Sanz (E-mail: psanz@if.csic.es).

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.

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