Tribological characterization of food products: Impact of the experimental setup

In food science, tribology has been gaining wider popularity over the last decade. Tribological measurements are performed with the aim of replacing or at least limiting sensory studies to evaluate texture properties of foods. Such sensory studies usually require trained panels, making them labour and cost intensive.
The setup of tribological measurements in food science is typically intended to mimic the processes in the oral cavity, i.e. the tongue touching the palate being lubricated by the food product under investigation. Naturally, the measurement setup can only be a simplification of this reality and various assumptions have to be made. For example, the ball-on-three-pins set up that is commonly used as measurement geometry can only roughly replace the geometry of the mouth in terms of dimensions and shape. Furthermore, commercially available tribopairs made from, e.g. glass, stainless steel or ceramic as well as PDMS, do not identically mimic sample-surface interactions found during food consumption. Additionally, preparatory steps for measurements can influence the gained results. This is particularly relevant in the formation, treatment and further handling of PDMS pins in the used measurement geometry.
... mehr
This contribution will show the impact of the variation of several experimental parameters during preparation and execution of a measurement method typical for the evaluation of the lubricating properties of foods. For this, a rheometer equipped with tribology cell is used. Stribeck curves obtained for two different food products, rapeseed oil and fulfat cow’s milk will be compared. These foods are chosen as they are typical for a wide range of different products: milk is an oil-in-water emulsion stabilized by proteins and represents various emulsion-based food products with aqueous continuous phase. Rapeseed oil, on the other hand, is hydrophobic. By comparing results for these two samples, the impacts of changes in measurement parameters for fat-based and water-based products as well as for homogeneous vs. dispersed systems can be highlighted. The studied measurement parameters comprise different manufacturing methods for the pins, resulting in deviating surface angles and pin strength, as well as different cleaning options during the measurement.
The poster will show the outcome of this research, i.e. the correlation between different manufacturing methods as well as cleaning methods and the influence on the tribological results of both food products.
The results will help to make the tribology of food products more accessible. Chances and limitations of the various setups will be highlighted enabling appliers to make an informed choice of measurement parameters for the characterization of their foods.