Influence of Stimulus Properties and Sensory Task Instructions on Oral Processing Behavior of Liquid Stimuli

This study determined the influence of texture properties and sensory task instructions on oral processing behavior of liquid stimuli. Oral processing of one sip of water, skimmed milk, thickened skimmed milk, cream and cream with poppy seeds was quantified using Surface Electromyography. Oral behavior was determined while subjects performed or did not perform sensory evaluation. Oral clearance time and time after the second swallow differed between liquid stimuli displaying large differences in texture properties, probably due to subjects attempting to remove oral coatings from the tongue surface during the oral clearance phase. Time to swallow decreased and total muscle activity increased when liquid stimuli were orally processed without performing a sensory evaluation. No differences in oral processing behavior of liquid stimuli were observed between different types of sensory evaluations (assessment of different sensory attributes). We suggest that some texture attributes of liquid foods might be perceived without requiring additional oral processing. We conclude that performing sensory evaluation influences oral processing behavior of liquid stimuli compared to not performing sensory evaluation.