Emulsion Essay

Introduction Emulsion is a mixture of two liquids that is not naturally mix together which one of the liquids being dispersed as small spherical droplets. There are two types of emulsion which is oil-in-water and water-in-oil. Oil-in-water emulsion is the dispersed oil droplets in an aqueous phase of a system. For example, milk dressing and mayonnaise. In contrast, water-in-oil emulsion is the dispersed of water droplet in an oil phase of a system. For example, margarine and butter. The substance that makeup the droplets referred as dispersed phase while that makeup surrounding liquid is called continuous phase. The process of converting two separate immiscible liquids into emulsion is known as homogenization. Temporary emulsification is created. Since oil and water is immiscible, the oil droplets will realign themselves as predicted by Stokes’ Law and recreate surface tension. This is because the difference surface tension makes them immiscible with one another.

Discussion

Interaction between water and oil creates an interfacial tension. The water molecules

Emulsifiers are classified as stabilizer to stabilize emulsion. Common emulsifier that usually use is lecithin which can be found in egg yolk. Lecithin act as a surfactant that will decreasing or complete diminish the surface tension to form emulsification. Lecithin in the egg yolk is commonly the only emulsifier that added into the emulsion. However, the vegetable oil may contain emulsifiers that inhibit crystallization. Lecithin will facilitate agglomeration during spray drying. During spray drying process, the hydrophobic portion of emulsifier will dissolve in the cocoa butter, orienting the hydrophilic portion of the phospholipid toward the surface of particle. (Van Nieuwenenhuyzen,1981). This increased affinity of the cocoa powder for water aids dispersion and