Beyond surface selection: The impact of different methodologies on tribological measurements

Emerging links between food friction and sensory texture have prompted an increase in food tribology studies. Soft tribological surfaces (e.g. elastomers) are used in these studies to mimic conditions in the oral cavity. However, measurement protocols and tribological surfaces vary among food tribological studies. Because the majority of these studies use empirical measurements, it is difficult to quantitatively compare their results. Although the effects of surface hydrophobicity, roughness, and modulus on friction coefficient measurements have been examined, there has been little study of variability due to differences in measurement parameters. Therefore, this study examined the effect of different measurement parameters on friction coefficient magnitude and variation. Tribological data were affected by multiple measurement parameters. A measurement protocol that yielded repeatable measurements with low variation was proposed based on these results. It is suggested that a standard protocol for food tribological measurements be adopted to enable proper data comparison among studies.