Phase field modelling of fracturing in frozen foods

In this study, we assess the fracture phase field method for simulating freezing damage in frozen foods. Inspired by Griffith's theory of fracture, this method enables explicit modelling of the nucleation and growth of cracks in brittle materials. Par-fried French fries are chosen as a case study, for which we have previously demonstrated experimentally that freezing damage occurs. The fries are modelled as a composite material consisting of a starch matrix with embedded ice crystals. Fracture properties of the starch matrix as a function of moisture content and temperature are taken from an earlier study on cereal flakes; however, uncertainty remains regarding the fracture energy of ice crystals. At low values of the ice fracture energy, macroscopic cracks form at the crust-core interface, in contrast to experimental observations. At higher values, only microdamage is predicted. Simulations in which the freezing temperature and crust thickness are varied show good agreement with experimental trends. Overall, we consider the fracture phase field method to be a promising simulation tool for investigating fracture behaviour in food materials.