Studies of “oral tribology” have attracted growing interests in food industry.However,there is a problem that the properties of the simulated oral material,the poly dimethylsiloxane (PDMS) is obviously different from the real oral surface.The ultraviolet/Ozone treatment was employed for PDMS surface modification,and the influences of PDMS surface properties on the evaluation of milk lubrication properties was investigated.The hydrophilicity,surface compositions and surface topography were characterized with contact angle goniometer,X-ray photoelectron spectroscopy (XPS) and Confocal laser scanning microscope (CLSM) respectively to identify changes of physical and chemical properties of PDMS surface.The tribological measurement was carried out on the UMT-3 tribometer to evaluate lubrication properties of milk with different fat content,and analyze the influence mechanism of surface physical and chemical properties of PDMS on milk lubrication characteristics.The results show that after UVO treatment for 1 h and 4 h,the contact angle is decreased from 110° to 82° and 60° respectively.The atomic ratio of oxygen vs.silicon on the PDMS surface is increased,and a glass-like SiOx film is formed to increase the hydrophilicity.The surface properties of the PDMS friction pair will affect the tribological performance.Among them,the coefficient of friction (COF) of the hydrophilic PDMS surface is higher than that of the hydrophobic PDMS surface.This is because the hydrophilicity of the PDMS surface after UVO treatment is improved,but the surface roughness increases,adhesion strength of the protein is increased.The COF of skimmed milk is higher than that of whole milk.This is because the decrease in fat content will affect fluid lubrication and film formation,resulting in an increase in COF.The study contributes to better understand the mechanism of milk textural sensation and systematic ex vivo evaluation of food taste.