Lennaert is a doctoral researcher at the Food Structure and Function research group(Ghent University). His research explores the interplay between the fat crystal network in lipid-based systems, oral processing, and mouthfeel perception. By applying rheological and tribological techniques, he aims to understand how structural changes of the crystalline network during oral processing affect the mouthfeel perception of lipid-continuous products upon consumption. Lennaert holds a master’s degree in Bioscience Engineering (Food Technology) from Ghent University and previously worked as a project manager at Cacaolab, where he gained hands-on experience on chocolate innovation and research.

About the lecture

Oscillatory rheology in food systems: linking microstructure to mechanical response

Oscillatory rheology is a technique to investigate the viscoelastic properties of food products, which originates from their intricate microstructures. In Small Amplitude Oscillatory Shear (SAOS) experiments, small deformations are applied to the material, allowing for the characterization of material’s viscoelastic behavior without altering its internal structure. This will be the focus of the first part of this lecture. Obtained parameters provide insights into the elastic and viscous properties and play an essential role in understanding texture and stability of food products. The second part of the lecture will delve into Large Amplitude Oscillatory Shear (LAOS) rheology, demonstrating how nonlinear rheological analysis can reveal structural breakdown mechanisms of food products under significant deformations. This approach is supported by advanced data processing techniques, providing a deeper understanding of how food structures respond to stress.

Understanding flow and tribological behavior in food systems

The flow behavior of food products is important with regards to food processing and sensory quality. In fat-based dispersions, this behavior becomes more complex due to the presence of a dispersed phase, leading to non-Newtonian characteristics. These can be studied through rotational rheology, which, depending on the sample, requires specific geometries to accurately measure parameters like yield stress, viscosity, and flow index. Tribology, on the other hand, offers insights into how materials behave between closely contacting surfaces. Originally associated with engineering applications (bearings, motors, brakes), tribology has become increasingly relevant in food science for assessing lubricative properties of food products. Within the oral cavity, the tongue and palate function as sliding surfaces, making tribological analysis key to understanding sensory attributes such as smoothness, creaminess, and astringency. This session introduces the core principles of rotational rheology and food tribology, during which some recent findings from the FSF research group on fat-continuous systems will be highlighted.