Emulsions

Mixtures in which fine droplets of one immiscible liquid are dispersed through another, such as oil-in-water (milk, mayonnaise, cream) or water-in-oil (butter, margarine) systems. Emulsions give foods much of their texture, mouthfeel and appearance, and keeping them stable is a central quality concern throughout shelf life. Stability is governed by Stokes’ law: smaller droplets and higher continuous-phase viscosity slow creaming, while emulsifiers and stabilisers guard against coalescence. Multiple emulsions (water-in-oil-in-water) enable reduced-fat spreads and controlled flavour release, and emulsion science underpins homogenised milk, infant formula and parenteral nutrition alike.