The influence of 6-n-propylthiouracil bitterness, fungiform papilla count and saliva flow on the perception of pressure and fat

• Fungiform papilla count mainly influences supra-threshold fat perception.
• PROP bitterness influences supra-threshold pressure perception.
• Stimulation with oil increases saliva flow.
• Increase of saliva flow influences supra-threshold fat perception.
• Classification of continuous data decreases amount of significant results.

It has been suggested that variations in oral physiology influence the ability to perceive fat. The aim of this study was to investigate how fungiform papilla count on the tongue tip, 6-n-propylthiouracil (PROP) bitterness, saliva flow and increase in salivary flow via oil stimulation influence the perception of fat. In addition, we examined the relationship between PROP bitterness and fungiform papilla count with respect to the perception of pressure. A total of 116 subjects participated in the physiological and pressure perception tests and 108 subjects participated in the fat perception tests. The subjects rated the pressure intensities of Von Frey filaments applied to the tongue tip and the fat content of different milk and cream mixtures and a high-fat emulsion. A-Not-A tests were conducted to measure the perception of the threshold fat contents and pressure intensities. The results show that the fungiform papilla count and saliva flow increase had a significant effect on the supra-threshold fat content intensity ratings. The supra-threshold pressure intensity ratings were only influenced by PROP bitterness. These results support the hypothesis that fungiform papilla play an important role in fat perception.