Formation, Structure and Functionality of Interfacial Layers in Food Emulsions
Emulsions, i.e., dispersions of liquid droplets in a non-miscible liquid phase, are overwhelmingly present in food products. In such systems, both liquid phases (generally, oil and water) are separated by a narrow region, the oil-water interface. Despite the fact that this interface is very thin (in the nanometer-range), it represents a large surface area, and controls to a great extent the physicochemical stability of emulsions. In this presentation, I give an overview of the aspects that govern the composition, structure and mechanical properties of interfaces in food emulsions, taking into account the complexity of such systems (presence of numerous surface-active molecules, influence of processing steps, dynamic evolution also due to chemical changes). This complexity can be addressed by developing a multi-scale approach to characterize relevant interfacial films, for which a range of methods has proved useful. Taking examples from my research projects, I focus on the link between interfacial properties and the physical, oxidative and digestive stability of emulsions at different levels, and point out trends to control stability via interfacial engineering.