Oral Parameters Affecting Ex-vivo Tribology

Abstract

Lubrication behaviour of foods has been explored in recent years and resulted in a better understanding of mouthfeel attributes, such as creaminess. Oral processing is a dynamic process that transfers the food into a bolus that is safe to swallow. This process is accompanied by a transition from rheology-dominant processes to tribology-dominant processes. In order to translate the oral movements into instrumental settings of analytical equipment a more precise quantification of the oral processing conditions is required. In recent years, several studies have delivered information about the oral movements. In this study, we focus on the lubrication behaviour of emulsions with different fat content and the role of instrumental settings on the measured lubrication behaviour.We found an effect of the type of movement performed with the tribometer. The oil concentration dependency of the measured friction was different when measured with a semi-ellipse movement compared to a linear or rotational movement. The deformation of the silicone and PDMS surfaces plays a role, replacing the silicone surface with a glass surface resulted in a different lubrication behaviour. Small changes in surface roughness of the PDMS surface affected the lubrication measured to a large extend. The impact of type of movement, type of surface and roughness of surface was not specific for the emulsions used; similar impact was found for rice starch dispersions. This investigation showed that subtle differences in the measuring conditions of the friction force can lead to different lubrication behaviour of (food) products and therefore conclusions.