Nanoemulsions: stability and physical properties

•Nanoemulsions have high optical clarity and good physical stability.•They enhanced bioavailability of encapsulated substances.•Selected preparation method depends on formulation desired.•Smaller droplets size lead to more homogeneous structure.•Structures with very small and well-distributed particles give stable systems.

Nanoemulsions present several advantages over conventional emulsions due to the small droplets size they contain: high optical clarity, good physical stability against gravitational separation and droplet aggregation, and enhanced bioavailability of encapsulated substances, which make them suitable for food applications. Depending on desired formulation, preparation method should be selected to optimize droplet size distribution since it strongly affects stability behavior. Systems with droplets diameter smaller than 200 nm and a monomodal distribution usually have a homogeneous structure, that is, a structure with well-distributed droplets that do not show flocs. A structure with these characteristics remains unchanged for long time, up to six months, given the nanoemulsion enhanced stability compared to conventional emulsions with the same formulation.