Generalized enthalpy model of a high-pressure shift freezing process

Abstract

High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work, we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition, the significant heat-transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier-Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature.

Mathematical Modeling of the Growth and Coarsening of Ice Particles in the Context of High Pressure Shift Freezing Processes

“…Recent advances in food preservation are related to development of the so-called high pressure shift freezing (HPSF) method, in which a sample is cooled under pressure (to a value close to 200 MPa) to a temperature close to its corresponding freezing point but it remains unfrozen. Once this temperature is reached throughout the product, pressure is released to produce different extents of supercooling at atmospheric pressure, which allows a very quick and homogeneous decrease of the tissue temperature to be achieved. − Such a shift in temperature quickly brings the water within the tissue well below its freezing point, hence causing homogeneous nucleation of a large number of very small ice particles. − Further growth of these particles decreases the freezing point of the remaining water by increasing the concentration of salts in it and finally stops the ice precipitation. Thus, the HPSF method allows avoiding the formation of relatively large, tissue damaging ice crystals during their relatively quick growth phase.…”

Potential Life Cycle Carbon Savings for Immersion Freezing of Water by Power Ultrasound

“…Conventional freezing methods include air blast, plate contact, immersion, and cryogenic using liquid nitrogen or CO 2 freezing. Recently, many new techniques for food freezing have been developed, such as magnetic resonance freezing (Anese et al 2012), high-pressure shift freezing (Fuchigami and Kato 1998;Smith et al 2012), application of ice nucleation active bacteria (Widehem and Cochet 2003), and ultrasound-assisted freezing (Zheng and Sun 2006).…”

Analysis and simplification of a mathematical model for high-pressure food processes

“…Nonlinear and non-isotropic thermal properties were used, which also led to a complicated numerical scheme. Smith et al [13] presented a generalized enthalpy model for a HP Shift Freezing process based on volume fractions dependent on temperature and pressure.…”