Size and location of ice crystals in pork frozen by high pressure assisted freezing as compared to classical methods.

MARTINO M; OTERO L.; SANZ P.D.; ZARITZKY NOEMI.

MEAT SCIENCE

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 1998 vol. 50 p. 303 - 313

0309-1740

In high-pressure-assisted freezing, samples are cooled under pressure (200 MPa) to -20°C without ice formation then pressure is released (0.1 MPa) and the high supercooling reached (approx. 20 ºC), promotes untform and rapid ice nucleation. The size and location of ice crystals in large meat pieces (Longissimus dorsi pork muscle) as a result of high-pressure-assisted freezing were compared to those obtained by air-blast and liquid Nitrogen. Samples from the surface and centre of the frozen muscle were histologically analysed using an indirect technique isothermal-freeze fixation). Air-blast and cryogenic fiuid freezing, having thermal gradients, showed non-uniform ice crystal distributions. High pressure-assisted frozen samples, both at the surface and at the central zones, showed similar, small-sized ice crystals. This technique is particularly useful for freezing large pieces of food when untform ice crystal sizes are required.