The development of tribological techniques for complex food formulations

The aim of this thesis was to develop tribological testing techniques in order to make them more closely relatable to oral processing and for those to be more accessible to researchers in academia and industry. An exploration of available tribological testing equipment, processing parameters and configurations were carried out to determine optimum testing conditions which could be related to oral processing. Two tribological testing systems were compared and model food systems analysed; one purpose built and commercially available for tribology and the other an attachment for a rheometer. Surfaces used in oral tribology experiments were also developed in two ways. The first being the surface chemistry of a polymer commonly used in oral processing tribology (PDMS) to more closely resemble the chemistry of oral surfaces. The second being textured surfaces to more closely resemble the texture of tongue. Lastly, all experiments aimed to investigate complex food systems, in particular particulate suspensions including agar fluid gels and astringent compound solutions including tannins found in wine and catechins found in tea. Both particulate suspensions and astringent compounds are commonly found in food systems and have been linked to affecting friction properties, sensory perception and consumer acceptance. The work presented in this thesis has shown the properties of the testing surfaces greatly affected the lubrication response. This information could then be used to develop tribological testing further in order to more closely resemble to oral cavity and allow accurate in-vitro assessment of food products to determine their lubricating performance when consumed