A review of recent trends in structuring oleogel-based emulsions for food applications

Abstract

Oleogel emulsions, a hybrid system combining oleogelation and emulsification, have emerged as a groundbreaking innovation in colloidal science, providing sustainable and healthier alternatives for food formulation. In the broadest sense, oleogel emulsions can be structured by dispersing oleogels in water or vice versa, stabilized by interfacially adsorbed food-grade particles or entangled network structures that retard droplet–droplet coalescence and phase separation. This review aims to provide an up-to-date overview of various oil-structuring approaches, highlighting their properties, different types of oleogel-structured emulsions, and the stabilization mechanisms involved in the formation of oleogel emulsions. Specifically, the factors affecting the characteristics of oleogel emulsions are summarized, including oil types, oil/water ratios, oleogelators, emulsifiers, and processing parameters. Additionally, recent studies on the application of oleogel emulsions in food products are discussed. Currently, there are three main mechanisms responsible for stabilizing oleogel emulsions: Pickering particles, network stabilization, or a combination of both. The droplet size, physical stability, and rheological properties of oleogel emulsions are strongly influenced by the nature and concentration of the oleogelators used as they gel the oil phase, which helps achieve the desired thermomechanical and microstructural properties. Similarly, changes in the type of oils or oil/water ratios used directly impact the physicochemical properties of the systems. These structured emulsions have been widely used as fat substitutes in various food products such as ice cream, cakes, spreads, sausages, margarine, burgers, and peanut butters.