Relating Tastant Concentration to Perceived Taste Intensity: A Mechanistic Understanding of pre-Transduction Events

Abstract

Transport of a taste stimulus from a beverage to the taste pores was computationally modeled in different anatomy scales: tongue's anterodorsal surface, circumvallate papillae and whole oral cavity in three dimensions. The models are based on the fundamental governing equations of transport phenomena. The stimulus delivery details were based on the experiments in literature or the sensory experiments run by the author. The fluid flow and stimulus transport were simulated based on the details of each anatomy. Realistic topology of a tongue’s surface, including lingual papilla histology, and the realistic anatomy of the oral cavity of a human subject were considered. For anterior surface of the tongue, results show that the uneven surface of the tongue has considerable influence on the persistence of supra-threshold stimulus concentration near taste pores. Time-concentration profiles were developed for various locations along the tongue’s surface. These profiles showed strong association with measured time-intensity (TI) profiles from literature, specifically, the rising phase, total duration and slopes. The computed concentration profiles can be used to better understand the course of events occurring during taste stimulation, which in turn will provide a better understanding of the relationship between a stimulus bulk concentration and its perceived intensity. For circumvallate papilla, the histological details such as secretion from von-Ebner gland into the cleft and a thin layer of saliva covering the papilla are included in the model. The experimental results show a relatively long intensity reaction time. The time-concentration profile of the tastant within the cleft shows that the secretion from von-Ebner gland contributes to the longer reaction time. Also, the comparison between the intensity and concentration profiles suggests that adaptation to taste takes place despite rising concentrations near taste buds. For the model on the whole oral cavity, the results show that the time-concentration profile near tongue is different than the time-concentration profile introduced upon stimulus delivery. Also, the computed concentration is studied against the intensity recorded under the same conditions. The results show a close association between the time-concentration profile near the tongue's surface and the time-intensity profile. The framework upon which the model is developed can be used for various consumption conditions, contributing to a quantitative understating of the relation between tastant concentration and taste intensity.