Abstract:
Solid food undergoes drastic structural changes during its transformation into a cohesive bolus, which play a key role in the perception of different textures during mastication. This article describes the structural changes in biscuits during mastication through particle agglomeration. Apparent particle size and bolus moisture content were measured at different chewing stages by image and gravimetric analyses. The microstructure of the ready-to-swallow bolus was also examined with light microscopy and cryo-scanning electron microscopy (cryo-SEM). The results reveal that moisture content increased at a parabolic rate during mastication, and the absorbed saliva increased apparent particle size and decreased particle number through agglomeration. Furthermore, both cryo-SEM and light microscopy indicate that a majority of the solid particles in the ready-to-swallow bolus were individual starch granules. The results from cryo-SEM also suggest that saliva composition varied locally within the final bolus, thereby implying that laminar mixing governs bolus formation during mastication.