Food Additives - Emulsifiers

Experiments in school and accidental discoveries at home have always taught us that oil and water do not mix. Oil floats on water. With years of growth and knowledge now we know that oil and water can form emulsions with the help of chemical substances called emulsifiers which acts to mix oil and water and form a homogeneous mixture.

An emulsifier is a molecule with one oil-loving and one water-loving end. Water loving end in food emulsifier is called hydrophilic tail and oil-loving end is called hydrophobic head. Food emulsifiers are also called emulgents. To make oil-in-water emulsion, such as mayonnaise, droplets of oil molecules are surrounded by the oil-loving end of the emulsifier molecules. This leaves the water-loving ends on the outside of the droplet, and so they stay in water, giving a homogeneous liquid rather than an unappealing mixture of water and oily droplets. In mayonnaise, the emulsifier is the phospholipids present in egg yolks – they are such successful emulsifiers that as much as 80% oil can be dispersed in the aqueous phase.

Emulsions are crucial to the consistency of a number of foodstuffs. Nature is good at making emulsions, and the classic example is milk, where a complex mixture of fat droplets is suspended in an aqueous solution. Nature uses proteins and phospholipids, and many emulsifiers used in modern food production are based on these natural substances.

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. 

Food emulsifiers make the food very appealing. Apart from this they impart the freshness and quality to the food. Natural food emulsifiers also prevent the growth of molds in food. 

Natural food emulsifiers are used in variety of foods. Some basic foods having food emulsifiers are: Biscuits, extruded snacks, cakes, soft drinks, toffees, frozen desserts, bread, margarine, coffee whitener, caramels etc.

Ice cream is another food that would not exist were it not for emulsifiers. It is both foam and an emulsion, and its texture results from the ice crystals and unfrozen water it contains. Emulsifiers are also important in bread and other baked products, where solid particles are dispersed in airy foam, are enhanced by emulsifiers.

The most frequently used raw materials for emulsifiers include palm oil, rapeseed oil, soy bean oil, sunflower oil or lard/tallow. Egg is the oldest emulsifier. Food drugs and cosmetics and pigment emulsions also require one or other kind of emulsifier. 

The emulsifiers that are used commercially come from both natural and synthetic sources include:

Emulsifiers	Note
Lecithins	These are mixtures of phospholipids and are usually extracted from sources such as egg yolk and soybeans. Uses include salad dressings, baked goods and chocolate.
Esters of mono-glycerides of fatty acids	These are made from natural fatty acids, glycerol and an organic acid such as acetic, citric, lactic or tartaric acid. The fatty acids are usually from a vegetable source, though animal fats can be used. Products that use them include ice cream, cakes and crisps.
Mono- and di-glycerides of fatty acids	semi-synthetic emulsifiers made from glycerol and natural fatty acids, which can be from either plant or animal sources. They are used in products like breads, cakes and margarines.

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.

Post by Faiz Lahori