Identification of multiple compartments present during the mastication of solid food.

The particle size distributions (PSDs) of two portion sizes (2g and 4g) of five foods (cake, cereal bar, muesli bar, cooked pasta and peanuts) after human mastication were determined. The PSD of the expectorated bolus and residual 'debris' rinsed from the mouth were each determined by wet sieving. There were significant differences in the PSD between food types, between portion sizes in the debris fraction and between the bolus and debris fractions. The latter suggests the existence of a two compartment system where particles are comminuted in at least one compartment within the oral cavity.