Modeling conductive heat transfer and process uniformity during batch high-pressure processing of foods

A numerical model for predicting conductive heat transfer during batch high hydrostatic pressure (HHP) processing of foods was developed and tested for a food simulator (agar gel). For a comprehensive evaluation of the proposed method, both "conventional" HHP processes, HHP processes with gradual, step-by-step pressure buildup and pressure release, and pressure cycling HHP processes were included. In all cases, good agreement between experimental and predicted temperature profiles was observed. The model provides a very useful tool to evaluate batch HHP processes in terms of uniformity of any heat- and/or pressure-related effect. This is illustrated for inactivation of Bacillus subtilis alpha-amylase, an enzymatic model system with known pressure-temperature degradation kinetics.