The role of intra-oral manipulation in the perception of sensory attributes.

To gain insight into the effect of oral processes on perception, we defined a set of five specific oral manipulations and investigated their effects on the perception of low and high fat versions of two semi-solid foodstuffs, vanilla custard desserts and mayonnaises. Behavior modifications ranged from simply placing the stimulus on the tip of the tongue to vigorously moving it around in the mouth. Sensory ratings for mouth-feel and flavor attributes were made 5s after placing the stimulus in the mouth, and after-feel attributes were rated immediately after swallowing. Most attributes showed a similar pattern, with lowest attribute ratings where the tongue's movement was restricted and gradually increasing ratings with increasing complexity of the tongue movements. An individual's normal oral processing behavior typically resulted in the most intense sensations of flavor and mouth-feel. Residence time for all mouth-feel attributes, except prickling, was determined by the time required for tongue movements. The exact tongue movements required for sensations appeared to be related to food groups and individual foods, rather than to specific mouth-feel attributes.