Experimental investigation and discrete simulation of fragmentation in expanded breakfast cereals

The fragmentation behaviour of brittle airy cereal product is studied both numerically and experimentally. A cereal food item is subjected to severe compression up to the densification stage. Experimental evidence of typical airy food behaviour is pointed out including elasticity, cell collapse and densification regimes. In order to better explain the observed behaviour, especially the resulting fragmentation, a numerical approach is proposed based on the discrete element method. Predicted results show good agreement with experimental mechanical responses. In particular, the maximum force values for fragmentation and the size of resulting fragments are in good accordance with experiments. Our numerical results show that the observed fragment size distribution is the consequence of a small number of rupture events of cell walls. This result highlights the role of the airy structure associated with a particular tendency to form a bimodal size distribution of fragments.