Nature+of+an+Emulsions

An emulsion consists of two immiscible liquids (oil & water), with one of the liquids dispersed as small spherical droplets in the other. Examples of common food emulsions: Cream, butter, margarine, mayonnaise, salad dressing, sausage, ice cream, cake, chocolate, spread, milk and egg yolk.
 * __Natural of an Emulsion __**

An emulsion consists of **three main components:**

__**A **____**queous Phase **__ Role as a solvent to the water- soluble components, as either the continuous phase in O/W emulsions or as the dispersed phase in W/O emulsions. The interfacial tension forces of water need to be reduced by the presence of emulsifiers. The formation of the emulsion is influenced by the pH, ionic strength and emulsifier concentration by altering the size of droplets and the interactions. Addition of hydrocolloids can affect the viscosity as well as emulsion formation, rheology and stability.

**__Oil Phase __** The oil phase is mainly in the form of triglycerides. It contains levels of di- and monoglycerides, polar lipids and free fatty acids. These three lipids tend to be surface-active, water-soluble and used as food emulsifier. Plant oils contain more unsaturated fats than those of animal origin, therefore liquid at room temperature. Fat is essential nutrient, it also imparts mouth feel to product and some flavor and aroma compounds. Important property: solidification or crystallization of the fat which has different rheological and textural properties to liquid oil (W/O emulsion). It can also change the texture of fat-continuous products. Crystallization of the fat allows the droplets to form solid networks that enhance structure and texture. The viscosity of the dispersed oil phase is also important for homogenization.

**__Surface Active Agent (Surfactant) __** Emulsifier has the role to form an adsorbed layer around the emulsion droplets which lowers the interfacial tension. It aids for emulsification and stabilizes the droplets against flocculation and coalescence. Emulsifiers need to be surface-active, therefore is amphiphilic. Emulsifiers can be either low molecular weight emulsifiers or macromolecular polymers. The most common polymeric emulsifiers in food are proteins.
 * Emulsifier **

Stabilizer is specifically aimed at polymers that are not surface-active. It is added to the aqueous continuous phase to impart long-term stability of O/W emulsion. Examples are xanthan, guar, carragenan, locust bean gum, Arabic, etc. Addition of the polymers in enough concentrations results in the effective encapsulation of the emulsion droplets by the polymer. This immobilization prevents flocculation of the droplets and reduces creaming.
 * <span style="font-family: 'Times New Roman',serif;">Stabilizers **


 * //<span style="font-family: 'Times New Roman',serif;">Multiple Emulsions //**<span style="font-family: 'Times New Roman',serif;">: In some emulsions the dispersed phase itself may contain globules of other phases, and can be either O/W/O type or W/O/W type.