Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Determination of the percentage of instantaneous ice I formed from water after expansion to atmospheric pressure

The aim of the work was to show experimentally if increasing pressure for a given temperature before expansion produce higher amounts of instantaneous frozen water and to study the supercooling phenomenon and its importance in the percentage of ice frozen after fast expansions. Samples were frozen by PSF at 100 MPa (-8.4°C), 150 MPa (-14°C) and 200 MPa (-20°C) as well as conventional air frozen (CAF), and liquid immersion freezing (LIF) at -20/-40°C. In the case of gelatine gel, CAF produced much larger ice crystals than LIF and PSF. LIF generated smaller ice crystals than those formed by PSF at 100 MPa. For the three PSF treatments, a higher pressure resulted in smaller ice crystals. In the case of Atlantic salmon, CAF produced larger and irregular ice crystals, resulting in serious deformation of muscle tissue. The ice crystals produced by LIF were fairly small but the cross-sectional area and roundness had large variations. PSF process significantly improved the microstructure of ice crystals (size, formation and location).

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Reported by

ECOLE NATIONALE D'INGENIEURS DES TECHNIQUES DES INDUSTRIES AGRICOLES ET ALIMENTAIRES
Domaine de La Geraudiere - BP 82225
44322 NANTES
France