# Probing the in-mouth texture perception with a biomimetic tongue

## TL;DR

This study introduces a biomimetic tongue system with fibrillar structures to quantitatively analyze in-mouth texture perception, accurately measuring viscosity and shear-thinning behavior under physiological conditions.

## Contribution

The paper presents a novel biomimetic tongue with fibrillar papillae and a fluorescent imaging technique for precise measurement of texture-related deformations.

## Key findings

- Accurately measures viscosity from 1 Pa.s to water's viscosity of 1 mPa.s.
- Validates technique with shear-thinning opaque dairy liquids.
- Quantitative agreement with existing theoretical models.

## Abstract

An experimental biomimetic tongue-palate system has been developed to probe human in-mouth texture perception. Model tongues are made from soft elastomers patterned with fibrillar structures analogue to human filiform papillae. The palate is represented by a rigid flat plate parallel to the plane of the tongue. To probe the behavior under physiological flow conditions, deflections of model papillae are measured using a novel fluorescent imaging technique enabling sub-micrometer resolution of the displacements. Using optically transparent newtonian liquids under steady shear flow, we show that deformations of the papillae allow determining their viscosity from 1 Pa.s down to the viscosity of water of 1 mPa.s, in full quantitative agreement with a recently proposed model [Lauga et al., Frontiers in Physics, 2016, 4, 35]. The technique is further validated for a shear-thinning and optically opaque dairy system.