Emulsifying agents are soluble in fat and water to allow uniform dispersion of fat in water. Emulsifying agents are also called emulsifiers and present in the food like butter, mayonnaise and salad dressing. These have one hydrophilic and one lipophilic part. These agents surrounds the oil droplets in water and reduces the tension between the two liquids thus impart stability.
Classification of Emulsifiers
These can be classified on the basis of chemical structure and mechanism of action. Under chemical structure category are synthetic, natural, auxiliary agents and finely dispersed solids. In the category of mechanism of action comes the monomolecular, multimolecular and solid particle films.
Natural emulsifying agents are derived from plant and animal tissues and mostly in the form of hydrated lypophilic colloids. These emulsifiers make the protective sheath around the droplets, give droplets a charge so that they repel each other and swell to step-up the viscosity of the liquid.
Natural ones are derived from vegetables, animals, semi synthetic and synthetic agents. Although natural agents are inexpensive, safe and non toxic but these are slow in action. So large quantity of emulsifier is required for proper action. Also the natural emulsifiers need preservatives as these are subjected to microbial growth.
The animal derivatives are stronger than the plant ones. The best example of this is lecithin and cholesterol. Some people are allergic to these so must be consumed after knowing the derivatives.
Both semi-synthetic and synthetic emulsifying agents are strong and require no preservative as these are not prone to microbial growth.
Applications of Emulsifying Agents
Emulsifiers are used in many types of food for stability and to reduce tension. Like vinaigrette if prepared only with oil and vinegar leads to unstable emulsion. To stabilize mayonnaise egg yolk lecithin is used as emulsifiers. Both natural as well as synthetic emulsifiers are used in food industry. Egg, soybean, rapeseed oil and palm oil are the common natural agents. Dairy products like cheese and ice creams use the emulsifying agents to improve the texture. Also the crystallization of candies is improved by them. Jarred peanut-butter and sauces are given more life with the use of correct emulsifier.
It is extensively used in pharmaceutical industry to make medicines more good to taste and easy to take. In pharmaceutical oil and water emulsions are basically used. These are also used in other industries like agriculture, paints and inks. Fertilizers and pesticides are given more stability with these.
Harmful Effects
Although the one used in food are completely safe and more over natural ones are safer than synthetic. But in some cosmetics certain harmful emulsifiers like polyethylene glycol (PEG) compounds, have been found that are carcinogenic. Also the emulsifying agents in body care products causes mild or severe allergies of skin.