High pressure calorimetry. Example of ice-water transition in selected biological matrix

A. LE BAIL, S. ZHU, A. OUSEGUI, R. ZUNIGA, V. TIRONI, M. ANTON-DE LAMBALLERIE AND H.S. RAMASWAMY

Praga

Conferencia; 44° Conferencia Internacional del European High Pressure Research Group (EHPRG); 2006

EHPRG

This paper presents details of a high pressure calorimeter designed to work up to 400 MPa in the temperature range -20°C to 80°C. This calorimeter can work in temperature scan mode at constant pressure or in pressure scan mode at constant temperature. The calorimeter was calibrated with Joule effect setup. The calorimeter was checked against the data of latent heat of pure water at high pressure (pressure range 50 – 180 MPa) proposed by Brigman. A comparison between pressure scan and temperature scan mode was done and demonstrated that better results were obtained at constant temperature. This calorimeter was then used to evaluate the latent heat of water in biological matrix such as a gel of methylcellulose (tylose), pork meat and fish meat. A model taking into account the dependence of the latent heat of the ice-water transition with pressure was developed and was compared with a good agreement to experimental data. A first example concerns the use of such a calorimeter to evaluate the phase diagram of aqueous solutions of selected salts. A second example concerns the high pressure thawing process applied to food systems. This application is under investigation in our group, which is member of the European Project SAFE ICE (QLK1-CT-2002-02230). Additional tests have been done using a modulated dsc at atmospheric pressure to determine the effect of HP process on the glass transition of selected food matrix.