Tribology of pekmez (grape molasses)-tahin (sesame paste) mixtures

A new field of texture analysis called “tribology” or “thin film rheology” that might explain the food texture throughout oral processing has become important. In this study, tribological experiments for samples containing pekmez and tahin at 30:70, 40:60 and 50:50 (w/w) were conducted by using a modified pin-on-disk tribometer. In the Stribeck curves hydrodynamic and boundary regions were determined. For the mixture containing pekmez:tahin at 50:50, hydrodynamic region started at a lower speed compared to other samples, which indicated a developing a thin lubrication film between contact surfaces. The friction decreased with the oil content of the sample. This was more profound in the lower speed region for all samples. Tribological data provided more distinct evaluation compared to the viscosity data which were close to each other due to similar composition of samples. Further research are needed on tribological properties of foods, their relation to rheology and sensory analysis.