Pressure shift freezing application on sea bass (Dicentrarchus labrax L.): Effects on quality and changes during the frozen storage

TIRONI, V., DE LAMBALLERIE, M. AND LE BAIL, A

Nantes (Francia)

Congreso; XIII Congreso mundial de Ciencia y Tecnología de los Alimentos IUFOST 2006; 2006

IUFOST

Quality of sea bass muscle treated by a pressure shift freezing process PSF (200MPa), in comparison with a conventional method (air-blast freezing ABF), was evaluated. After storage at -15 and –25 °C (0, 1, 3 and 5 months) samples were thawed (air-blast). Microstructure, muscle proteins alterations (DSC, sarcoplasmic SPE and myofibrillar proteins extractability MPE); water holding capacity WHC of raw and cooked muscle, were analyzed. Microstructural analysis showed a notorious decrease of the cell damage when PSF was applied, with not shrinkage of cells due to the formation of very smaller ice crystals; no differences because of the time and temperature of storage were evident. PSF produced a partial denaturation of myosin and sarcoplasmic proteins, as well as reduced extractability of sarcoplasmic and myofibrillar proteins (time 0). After frozen storage, myosin denaturation was evident for ABF muscle at both temperatures, while PSF muscle presented only small changes; thus, myosin entalphy denaturation showed comparable values for both freezing processes after frozen storage. MPE decreased significantly in the case of ABF during the storage at both temperatures, achieved comparable values to those of the high-pressure treated systems. WHC of the raw muscle decreased because of the PSF process, but differences between PSF and ABF samples disappeared after cooking; this behavior was constant for all storage time/temperature conditions. In conclusion, PSF process appeared as a promissory new freezing technology to be applied to fish muscle.