A bioinspired setup to evaluate food graininess via tactile friction and vibration

Current tribological methods show unsatisfactory performance in evaluating food graininess, neglecting the existence of tactile vibration in human oral perception. Inspired by this biological mechanism, we proposed a novel setup that can mimic the oral tactile sensation. Taking chocolate syrups and barley grass gels as model foods, feasibility tests show our setup capable of acquiring the tactile friction and vibration information. The optimal acquisitions are obtained at the sliding speed of 0.5 mm/s and normal force of 200 mN. Simultaneously, friction coefficient and the vibration amplitude at the frequency of 24 Hz (on Y-axis) are extracted as the feature parameters. Results show that the vibration amplitude is more informative than the friction coefficient in discriminating graininess levels, and integrating both feature parameters can improve the discrimination performance. By unveiling the importance of tactile vibration, this study paves the way for developing new food texture analyzers based on tactile sensing techniques.