Food Microstructures: Emulsions

Abstract

Emulsions are complex fluids, the flow and rheology of which are dictated not only by the rheology of their components, but also by the intricate colloidal interactions between the dispersed emulsion droplets. The behaviour of emulsions in the mouth is a complex, multifaceted process that is the net product of physical, textural and chemical stimuli from both the fat and the structures formed by the emulsion droplets. The physical processing of the emulsion in the mouth – including mixing, shear and the role of saliva – also affects the structure and stability of the emulsion. This chapter outlines the key aspects of emulsions that make them unique as food structures and the mechanisms underpinning their physicochemical behaviour, which may impact the sensory perception of fat. The complex physicochemical behaviour of emulsions is one of the reasons why engineering acceptable emulsion-based foods with reduced levels of fat is so challenging, but we discuss some of the main approaches that have been used to date.