Investigating changes in sensory stickiness perception with age

• Subjects aged 22–30 and 56–70 undertook TI for stickiness and gritty/graininess.
• Subjects were served cashews and blended cashews (to simulate a swallow-able bolus).
• Moisture content and rheology of the subject’s boluses was also assessed.
• TI curves were similar between age groups.
• Bolus properties and oral processing behaviour was similar between age groups.

A recent study had shown that a group of younger subjects (21–29 years) selected the term sticky at a significantly greater rate than a group of older subjects (55–70 years) using the Temporal Dominance of Sensations (TDS) methodology with a range of nuts. It was hypothesised that differences between age groups in bolus properties was causing greater sensory stickiness intensity to be perceived by the younger subjects. The aim of the current study was to assess the physical properties of the bolus, as well as the dynamic perception of stickiness using Time Intensity (TI), of the same subjects from the previous study. Subjects undertook a mastication trial where they chewed cashews and expectorated the bolus for assessment of its physical properties. Subjects also undertook a TI task with two separate products: cashews and blended cashews (blended to a particle size that simulated a ready to swallow food bolus), without training of high and low intensity anchors of each sensation. Results showed the bolus properties and oral processing behaviour was similar between the two age groups. Results also showed the dynamics and magnitude of TI for stickiness was similar between the two age groups. The study suggests variables other than bolus properties and stickiness intensity are responsible for differences in the TDS selection of stickiness between younger and older age groups.