Modelling heat transfer in high pressure food processing: a review

Abstract

The most claimed advantage of high-pressure food processing as compared to thermal processing is that pressure acts instantaneously and uniformly through a mass of food independently of its size, shape or composition. Nevertheless, thermal gradients are established in the products after compression and cause inhomogeneities in the pursued pressure effect. Modelling heat transfer in high-pressure food processes can be a useful tool to homogenise and optimise these treatments. The main difficulty is the lack of appropriate thermophysical properties of the processed materials under pressure. When modelling high-pressure processes at subzero temperatures, pressure/temperature phase transition data and latent heat are also needed. Those for water are known, but there is a total lack for those corresponding to components relevant to foods. Moreover, the precise mechanisms that rule high-pressure shift freezing and induced thawing are not yet clear and so it hinders modellisation. This review collects the difficulties found and the advances made up to date in modelling heat transfer in high-pressure processes, including those performed at subzero temperatures.