Friction study of honey-water in a mimicked soft oral environment

Abstract

Food oral tribology plays an important role in studying the oral processing behavior of foods. This article explores the lubricity of different mass fractions of honey-water solutions (HWS) combining experimental and simulation study. Friction experiments are performed in simulated soft oral environment, and the complete Stribeck curve is successfully constructed. It is found that as the mass fractions of honey increase, the friction coefficients decrease and the curves move towards higher Vη (speed × viscosity) values. Higher viscosity and wettability enhance the film-forming and entrainment ability of the fluid, while reducing the friction coefficients in the boundary and mixed regimes. However, changes in wettability have little impact on the elastohydrodynamic lubrication regime of pure honey. In addition, a lubrication model is established using finite element method to examine the fluid movement in the lubrication area. The distribution of lubrication film exhibits a horseshoe shape. Influences of the sliding speed, fluid viscosity, and solid viscoelasticity on the distribution of fluid pressure and film thickness are revealed. This study provides guidance for exploring the oral processing behavior of fluid foods and improving the pleasure of eating.