Understanding frying-induced water loss and oil uptake dynamics in porous food systems in relation to their starch and protein constituents

Deep frying is the process of cooking and (partially) dehydrating food by immersing it in oil at typically 170 to 180 °C. Many foods are fried, including e.g. tubers and slices thereof, vegetables, meat and wheat dough-based products (e.g. donuts). Deep frying involves complex heat, oil and water transfers which impact the quality of the resultant foods. That high fat foods are calorie-rich challenges the food industry to minimize oil uptake during deep frying. However, to do so without losing their distinctive palatability, it is essential to understand the mechanisms of water evacuation from and oil uptake by the product during frying. This process is, at present, not fully understood. Nevertheless, the main hypothesis of this research proposal is that starch and gluten based formulations can be optimized to design specific structures of fried foods with lowered fat content while still maintaining their desired textural properties. The objective of this project is to build and validate a model describing the dynamics of frying-induced water loss and oil uptake in porous food matrices in relation to changes in starch and protein. To reach this objective, insights will be gained at different length scales: (i) at the molecular level, the impact of frying on starch transition and protein polymerization in starch-gluten-water systems will be assessed in relation to changes in the microscopic model food architecture and oil and water transport phenomena and (ii) at the microscopic level, changes in porous microstructure characterized by the 3D network of pores and throats of food will be related to oil and water transport properties during frying using microscale network models of multiphase flow.