Gelling Agents, Stabilisers and Thickeners: Origins and Uses
The substances belonging to this group are high molecular weight compounds. They are usually proteins, such as gelatin, or complex carbohydrates like pectins , starches, alginates and gums. Most are long chain molecules (polymers) that are made up of hundreds of linked units called monomers. They can be divided into a number of categories depending on their source of origin.
Many gelling agents, stabilisers and thickeners occur naturally in foods.
|Seeds||The outside of the seeds are removed and the inner part (endosperm) is ground into a powder which can be used as a stabiliser, thickener or gelling agent||Guar gum||E412|
|Locust bean gum||E410|
|Plant exudates||Some plants ooze out sticky substances that can be harvested and used||Gum arabic (acacia gum)||E414|
|Citrus fruits and apples||Pectin is dissolved out from fruits, filtered and then precipitated from the solution||Pectin||E440|
|Plant materials||Plant cells are made up of cellulose. It is isolated and used as the raw material for a series of modified cellulose compounds||Cellulose||E460|
|Seaweed||Seaweeds are often farmed commercially and used to obtain a variety of thickeners, gelling agents and stabilisers||Agar||E406|
|Maize and potato||Starch is obtained from maize and potatoes before being modified||Starches||E1404-1451|
Use in Foods
Many foods can be made at home without the addition of gelling agents, thickeners or stabilisers. So why are these additives used so widely in the food industry?
Food cooked at home is often produced in small quantities. It is usually eaten shortly after it has been prepared and cooked. Processed foods, on the other hand, are produced in comparatively large quantities. They are expected to have a far longer shelf life, which could even be years in some cases. This may require processes such as freezing or high temperatures in canning or UHT processing. Gelling agents, stabilisers or thickeners need to be added to commercially-produced food to maintain their structure and physical properties during this processing.
Fruits such as currants, damsons, gooseberries, lemons and bitter oranges are rich in both acid and pectin. These can easily be made into jams. However, fruits such as strawberries, raspberries and cherries need the addition of a small amount of pectin to form a jam.
The current use of many of these agents in food may seem unnecessary. However, the modern variety of foods eaten have specific requirements. These include: different processing and cooking techniques, various storage methods and the needs of shops.