The Effect of Oral Tactile Sensitivity on Texture Discrimination and Mastication

Texture perception is one of the most important factors in food acceptance. Individual differences between consumers for perception and oral processing techniques makes research on related topics difficult to find overall effects. It is thought that individual differences in texture perception could be caused by oral sensitivity or mastication behavior. The first hypothesis is that the variation in texture perception across populations is dependent on oral tactile sensitivity and masticatory performance. To address this hypothesis, the study was aimed to measure tactile acuity with a battery of tests and quantitate the relationship to masticatory performance. In general, sensitivity and masticatory performance in the younger age groups was superior to that of older adults (p < 0.0001). A positive linear trend was also found between bite force sensitivity and masticatory performance with younger participants, a trend not found in older participants. No significant relationship between age groups for bite force sensitivity and masticatory performance was found, suggesting that age-related declines in bite force sensitivity are not a significant cause of altered masticatory performance. The second hypothesis is that as oral sensitivity decreases so will a participant’s ability to discriminate texture differences, since there will be less feedback from the oral cavity. We noted that oral sensitivity was not a significant factor when looking at differences in discrimination ability between high and low sensitivity groups. However, the study found that multiple masticatory behaviors were being modulated by oral sensitivity, including overall chewing patterns used (p < 0.0001). More specifically, those in the high sensitivity group used more stochastic chewing movements, while those in the low sensitivity group were found to use crescent and crossed-shaped chewing cycles. It was also noted that in the high sensitivity group the jaw moved further distances (p < 0.0001) in all phases (opening and closing) and moved at a higher velocity when opening (p < 0.0001) but not when closing, when compared to the low sensitivity group. These results help bolster evidence that sensitivity and masticatory performance are related and, as previously reported, both decline as people age (Calhoun, Gibson, Hartley, Minton, & Hokanson, 1992).

This thesis consists of 2 published experiments (Journal of Texture Studies 2018 - Chapter 1 and Physiology and Behavior (in Review) - Chapter 2).