Emulsifiers and stabilisers

An emulsion is a dispersed system of two immiscible phases. Emulsions are present in several food systems. In general, the disperse phase in an emulsion is normally in globules 0.1-10 microns in diameter. Emulsions are commonly classed as either oil in water (O/W) or water in oil (W/O). In sugar confectionery, O/W emulsions are most usually encountered, or perhaps more accurately, oil in sugar syrup. One of the most important properties of an emulsion is its stability, normally referred to as its emulsion stability. Emulsions normally break by one of three processes creaming (or sedimentation), flocculation or droplet coalescence. Creaming and sedimentation originate in density differences between the two phases. Emulsions often break by a mixture of the processes. The time it takes for an emulsion to break can vary from seconds to years. Emulsions are not normally inherently stable since they are not a thermodynamic state of matter. A stable emulsion normally needs some material to make the emulsion stable. Food law complicates this issue since various substances are listed as emulsifiers and stabilisers. Unfortunately, some natural substances that are extremely effective as emulsifiers in practice are not emulsifiers in law. An examination of those materials that do stabilise emulsions allows them to be classified as follows ... 

A stable foam is likely to have ingredients that are in a low energy state at the air-liquid interface. Substances that fit this description include proteins, emulsifiers some fats and fat components such as diglycerides monoglycerides and fatty acids. Food law uses the term emulsifier and stabiliser to cover the situation where the ingredient is stabilising an emulsion rather than helping to form it. 

Food colours Flavours and sweeteners Fat emulsifiers and stabilising agents Flour improvers - antistaling agents and bleaches Antioxidants Preservatives... 

Graven, S. Application of Emulsifiers and Stabilisers in Selected Dairy Products. Grindsted Technical Paper 215 (1989). 

Emulsions are not normally inherently stable since they are not a thermodynamic state of matter - a stable emulsion normally needs some material to give it its stability. Food law complicates this issue since various substances are listed as emulsifiers and stabilisers. Unfortunately, some natural substances that are extremely effective as emulsifiers in practice are not emulsifiers in law. An examination of those materials that do stabilise emulsions allows them to be classified as follows ... 

In this section, emulsifier means a material that is on the list of permitted emulsifiers and stabilisers - there are some materials that are extremely effective emulsifiers but which, in fact, do not qualify as emulsifiers in food law. The main examples are the proteins contained in milk they are effective at emulsifying oils and fats but do not qualify for the legal description of emulsifiers. 

Silicone resin emulsions. With the aid of suitable emulsifiers and stabilisers, insoluble silicone resins can be converted into water-soluble emulsions and can be diluted with water. Such emulsions are used as water-repellent additives for plaster or silicate emulsion paints as well as for the surface treatment of mineral powders such as perlite, aerated concrete granules, and so on. 

Apart from the volatile constituents, cold-pressed citrus oils contain a non-volatile fraction in varying amounts (1% in orange oil, up to 10% in cold-pressed lime oil), which is associated with emulsifying and stabilising properties. 

Nonionic surface active agent. Food emulsifier and stabiliser. 

Tragacanth is used as a thickening agent, emulsifier and stabiliser in salad dressings, ice creams, pastry fillings and other products. 

In food applications, dextrans Leuconostoc mesenteroides strains product) have been used, usually in combination with other polysaccharides such as gum arabic, for purposes similar to other hydrocolloids. They are highly effective emulsifiers and stabilisers of emulsions of oil in water. They bind water and inhibit the crystallisation of saccharose. Much more extensive use has been found for dextran in pharmacy and medicine (replacement of blood plasma) and in analytical chemistry as a chromatographic material for gel filtration and other applications. 

Emulsifiers and Stabilisers.—These are substances which when added in small quantities promote the formation of colloidal systems and render them less liable to spontaneous precipitation. Gum acacia, gum tragacanth, soaps, saponins, gelatin and lecithin are representative stabilisers used industrially. yolk, on account of the lecithin it... 

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