Introduction

Emulsion-based food products exhibit different physicochemical and organoleptic characteristics,  e.g. appearance, aroma, texture, taste and shelf life These happened as a result of different ingredients and processing conditions used. The manufacture if the emulsion-based food product with specific quality attributes depends on the selection of the most appropriate raw materials( water, oil, emulsifiers, thickening agent, minerals, acids, bases, etc) and processing conditions (mixing, homogenization, pasteurization, sterilization, etc).
 * __Introduction __**

**__Surface and Interfacial Tension __** **//Surface tension //** : A force to reduce the surface area acts on the surface of the water. **//Interfacial tension //** : A kind of surface tension acts on the interface  (when two immiscible substances in contact) so that they separate from each other. When an emulsion is formed, surface contact area increases, the total interfacial tension also increase. **//Surfactant //**  weakens interfacial tension and changes the properties of an interface. **//<span style="font-family: 'Times New Roman',serif;">Food emulsifier //** **<span style="font-family: 'Times New Roman',serif;">: **
 * 1) <span style="font-family: 'Times New Roman',serif;">Surfactant for food which distinguishes from other surfactants for other purposes.
 * 2) <span style="font-family: 'Times New Roman',serif;">Consists of hydrophilic and lipophilic (hydrophobic) parts within it
 * 3) <span style="font-family: 'Times New Roman',serif;">Reduce the interfacial tension (make the mixing of oil and water easy)