A modeling approach for evaluating process uniformity during batch high hydrostatic pressure processing : combination of a numerical heat transfer model and enzyme inactivation kinetics
Faculty of Sciences. Bioscience Engineering
Engineering sciences. Technology
Innovative food science & emerging technologies. - Amsterdam
, p. 5-19
A numerical conductive heat transfer model for calculating the temperature evolution during batch high hydrostatic pressure (HHP) processing of foods was tested for two food systems: apple sauce and tomato paste. Hereto, relevant thermal and physical properties of the products were determined. For a comprehensive evaluation, both conventional HHP processes with gradual, step by step pressure build-up and pressure release were simulated. In all cases, satisfactory agreement between experimental and predicted temperature profiles was obtained. The model provides a very useful tool to evaluate batch HHP processes in terms of uniformity of any heat- and/or pressure-related effect. Uniformity of inactivation of Bacillus subtilis α-amylase and soybean lipoxygenase during batch HHP processing was evaluated. Hereto, a theoretical as well as an experimental approach was used. The residual enzyme activity distribution appeared to be dependent on the inactivation kinetics of the enzyme under consideration and the pressuretemperature combinations considered. Good agreement between the theoretical considerations and experimentally obtained activity retentions was found for Bacillus subtilis α-amylase. In case of soybean lipoxygenase, less agreement was found. This work presents a first step in the development of indicators to assess process uniformity in HHP processing of foods.