Porous media based model for deep-fat vacuum frying of potato chips

摘要

Vacuum frying is an alternative method to the traditional atmospheric deep-fat frying that offers the health benefits associated with lower concentrations of acrylamide and less adverse effects on oil quality while still preserving the natural color and flavor of the product. A fundamental-based understanding of the process benefits its design and optimization. As potato chips are relatively thin in size and vacuum frying is a more complex operation than atmospheric frying, it is difficult to experimentally measure properties of the chip and hence the usefulness of modelling such a process. A multiphase porous media model involving heat and mass transfer within a potato chip was implemented in a commercial CFD program. Moisture evaporation was modelled using a non-equilibrium approach. Simulations were run at different frying pressures of 1.33 kPa, 9.89 kPa, 16.7 kPa, and 101 kPa. Good agreement between predicted and literature experimental moisture, oil, and acrylamide content was obtained. The model showed that regardless of fryer pressure, the core reached a pressure of approximately 50 kPa higher than the surface during early frying. The highest pressure difference occurred at different times and last for different periods of time based on frying conditions. The model demonstrated that acrylamide formation could be modelled as a function of chip temperature rather than the more general, oil temperature.