Oral movements and the perception of semi-solid foods.

Here we review the role of oral movements in the perception of food attributes, particularly for semi-solid and liquid foods ingested almost in ready-to-swallow form. An overview of a series of instrumental and sensory studies suggests clear links between the type of sensation and the time point of processing in the mouth. Some commonly-reported sensations, such as thickness, are relatively immediate and reflect the bulk properties of food bolus when the food is relatively intact. Others, such as fattiness and melting, reflect both bulk and surface properties and follow considerable oral processing when the food is relatively degraded. Yet others, such as fatty after-feel, are only fully developed after swallowing is complete. In addition, oral processing also plays an important role in the generation of aroma and taste sensations. Most of these in prior vivo studies have now been confirmed by in vitro work using a modified rheometer, dubbed the Structure Breakdown Cell (SBC), wherein the mechanical and enzymatic break-down of food can be monitored directly and related to sensory profiles generated by trained panelists.