Preliminary analysis of mastication dynamics and fragmentation during chewing of brittle cereal foods

- Brittle airy cereal foods display same mastication dynamics.
- Compression is the dominant deformation mode and shear can be discarded.
- Different fragmentation states before swallowing are determined by image analysis.
- Bolus homogeneity is correlated to the work imparted by crushing in a Kramer cell.

We studied the masticatory behaviour of five commercial brittle cereal foods, with different formulations, shapes and mechanical properties, chewed by an individual. The investigation of oral behaviour consisted in a simultaneous recording of jaw kinematics and muscle activity by electromyography (EMG) and we also determined the food size distribution at the swallowing point by image analysis. Similar behaviour was found for the evolution of all criteria, and especially the predominance of compression, which could be attributed to the brittle behaviour of the foods. The amplitude of the jaw motion decreased with the number of chewing cycles, or sequence duration, whereas the maximum mastication force led to the larger fragments of cereal foods when bolus was close to the swallowing point. Despite similar texture, mechanical properties, assessed by Kramer shear cell, influenced mastication work and bolus homogeneity.