Lubrication studies of fluid food using a simple experimental set up

Studies of "oral" tribology and "oral" lubrication have attracted growing interests among food researchers because of their important roles in oral textural sensation. However, to access a feasible technique for such studies is still a challenge to many food researchers due to the high cost of a commercial tribometer. In this work, a simple experimental set up has been constructed and tested for its feasibility and reliability for lubrication studies. The ultimate aim is to develop a reliable and low-cost technique for food lubrication studies and oral texture sensation studies. The design is based on a standard texture analyser manufactured by Stable Microsystems, with few additional simple fittings and attachments. This design is capable of conducting friction/lubrication measurements over a wide range of sliding speed (0.01-40 mm/s) and at any chosen surface load. The set up is convenient to operate and easy to set controlled experimental conditions (e.g. sliding speed, surface load, temperature, etc). Syrup solutions and evaporated milk were used as examples of near-Newtonian and non-Newtonian fluids for feasibility tests and results were reliably reproducible. Friction coefficients obtained for syrup solutions were comparable to those reported in literature. Stribeck curves covering the boundary regime, mixed regime, and hydrodynamic regime can also be constructed. Our results demonstrate that this design provides a low-cost alternative for food lubrication studies. Details of experimental set up, its advantages and limitations were discussed in this paper