Food emulsifiers act as an interface between the conflicting components of food like water and oil. While preparing the food, often conflicting natural components of food have to be combined into a consistent and pleasing blend. Each component of food (carbohydrate, protein, oil and fat, water, air, etc.) has its own properties which are sometimes conflicting to one another just like oil and water. To make the two components compatible, emulsifiers are used.
An emulsifier is a molecule with one oil-friendly and one water-friendly end. Water friendly end in food emulsifier is called hydrophilic tail and oil-friendly end is called hydrophobic head. Food emulsifiers are also called emulgents. In this way droplets of oil are surrounded by the emulsifier molecule, with the oil core hidden by the water-friendly tails of the emulsifier. A classic natural emulsion is milk, which is a complex mixture of fat suspended in an aqueous solution. Nature's emulsifiers are proteins and phospholipids (lipids means fat soluble phosphate is water soluble). Egg is commonly used as an emulsifier. Some emulsifiers also act as anti-caking agents like Magnesium Stearate, Sodium, potassium and calcium salts of fatty acids. Few others like Sorbitan monostearate are emulsifier as well as stabilizer.
The most frequently used raw materials for emulsifiers include palm oil, rapeseed oil, soy bean oil, sunflower oil or lard/tallow. Egg happens to be the oldest emulsifier. Basic emulsifier production involves combining oil (triglyceride) with glycerol that results in monoglyceride. The type of triglyceride used in the reaction determines the type of emulsifier obtained. Unsaturated triglycerides produce fluid products such as oil while saturated triglycerides result in pasty or solid structures like butter. Monoglycerides can be combined with other substances, such as citric acid and lactic acid, in order to increase their emulsifying properties. Food drugs and cosmetics and pigment emulsions also require one or other kind of emulsifier.
On the basis of their hydrophilic groups, there are basically four categories of natural food emulsifiers and emulsifiers. These areFood emulsifiers make the food very appealing as without emulsifier the water and the oil content in food will look separate, which will give very unappealing appearance. Apart from this they impart the freshness and quality to the food. Natural food emulsifiers also prevent the growth of moulds in food.
Emulsifiers are used in creams and sauces, bakery, and dairy products. They may be derived from the natural products or chemicals. Common emulsifiers are lecithins, mono- and di-glycerides of fatty acids esters of monoglycerides of fatty acids and phosphated monoglycerides.
Natural food emulsifiers are used in variety of foods. Some basic foods having food emulsifiers are: