Oil and water never mix but yes they do form emulsions.
As an experiment try adding some drops of oil in a glass of water and shake it…What do you find?
How long you shake or stir but oil will keep floating on to the surface of water until we add some emulsifier in it.
WHAT IS EMULSIFIER?
An Emulsifier is a molecule with one oil-loving end and another water-loving end. This oil friendly end in food emulsion is known as hydrophobic head and water friendly end is known as hydrophilic tail. Food emulsifiers are also termed as Emulgents. Emulsions work to make water and oil dispersed into a stable and homogeneous solution by forming smooth emulsion. When water and oil are mixed in presence of an emulsifier, oil droplets surround by the emulsifier molecule, and the oil core is hidden by hydrophilic tails of the emulsifier.
The complex mixture of fat present in milk, suspended in an aqueous solution makes it a classic example of emulsion. In food industry Egg yolk was probably the first emulsifier. The usage of egg yolk started in early 19th century. but since the stability of egg yolk is very less manufacturer shifted their focus on a new emulsifying agent derived from soybean known as lecithin. If we look at the History, ancient Greeks utilised the emulsifying power of beeswax in many cosmetic products. Further scientific research and investigation on emulsifiers introduced certain derivative of fatty acids like mono and di-glycerides which are later patented for the production of ice-creams.
Nowadays, emulsifier food additives play an important role in the manufacture of wide range of food products such as mayonnaise, creamy sauces, candy, many packaged processed foods, confections, margarine and a range of bakery products.
TYPES OF FOOD EMULSIFIERS
The most used emulsifiers are soya bean, sunflower oil, palm oil, rapeseed oil, Egg Yolk emulsifying agent lecithin, Honey, Mustard, Soy lecithin, CSL Calcium Stearoyl Di Laciate, Sugar Ester (SE), Acetylated Monoglyceride (AMG), Lactylated Monoglyceride (LMG), Polyglycerol Ester (PGE), Sorbitan Ester (SOE), PG Ester (PGME), Monoglyceride (MG). The process of production of basis emulsifier includes a combination of oil (triglycerides) and glycerol which results in formation of monoglyceride. The type of emulsifier produced totally depends on the triglyceride used. Like an unsaturated triglycerides produce fluid products such as oil whereas the saturated triglycerides form a pasty or solid structures like butter. Monoglyceride can be used to increase the emulsifying properties of citric acid and lactic acid.
On the basis of hydrophilic groups, there are four types of emulsifier
• Anionics
• Non-ionics
• Cationics
• Amphoterics
APPLICATIONS OF FOOD EMULSIFIERS
Emulsifier plays a very important role. They don’t just provide an appeal to the product but also keeps them fresh. They help in maintaining the quality of the food. Imagine without emulsifier how the water and oil content will remain separated. Natural food emulsifiers also prevent the growth of moulds in food. They are used in various dairy products, ice-creams, sauces and bakery products.
Emulsifiers can be derived from the natural products or chemicals. Variety of foods are produced by the use of natural emulsifiers like biscuits, extruded snacks, cakes, soft Drinks, caramels, toffees, frozen desserts, margarine, coffee whitener, bread
SPECIFIC ROLE OF EMULSIFIER IN FOOD PRODUCTS
BREAD
Emulsifiers are not necessarily required for bread production, but the bread produced without emulsifiers are dry, hard and low in volume and it stales easily. Just the addition of 0.5% of emulsifier in dough is enough to obtain a soft, fluffy bread. Two types of emulsifiers are used in bread 1. Dough strengthens (e.g. diacetyl tartaric acid esters (E 472e) 2. sodium or calcium stearoyl-2-lactylate (E 481, E 482)) and a dough softener (e.g. mono- and di-glycerides of fatty acids (E 471)). The main function of dough-strengthening agents is to make dough stronger, improved in texture and volume. Dough-softening agent helps in obtaining a softer crumb structure with increased shelf-life.
CHOCOLATE
To provide right consistency in a chocolate 0.5% of lecithin (E 322) or ammonium phosphatide (E 442) is added. Emulsifiers added in chocolates provide right consistency and it helps in easy mould of the product whether it be a chocolate bar or a chocolate ball.
You all must have noticed a white layer on the surface of a refrigerated chocolate. This layer is called as bloom. Addition of Sorbitan tristearate (E 492) in the mixture can delay the development of bloom.