Carrageen is an ingredient with several purposes, usually sold as a powder.
It is used commercially in desserts, jellies, and ice cream. It causes stuff to gel at room temperature with no refrigeration needed. Substances gelled with it can be firm or soft, and have a high or low melting point, according to desire.
It is also used to stabilize liquids that have "bits" in them and help the "bits" in them to stay suspended in the liquid, rather than sinking to the bottom. For instance, in chocolate milk, it stops all the chocolate from sinking to the bottom. It can also be used for the opposite purpose, to cause bits to sink to the bottom. In this way, it is used to clarify beer, vinegar and wine.
In ice cream, it helps prevent ice crystals from forming, as well as improving the feel of the ice cream in your mouth. It doesn't interact with milk proteins, so it doesn't affect the taste / texture of dairy products.
It thickens sauces and salad dressings. In already-made meat patties and in luncheon meats and other prepared meats, it can be used as a substitute for fat, and to help increase weight.
It reinforces gluten structures, allowing cheaper soft flours to be used for pasta.
The behavioural characteristics of the Carrageen are influenced by the species of seaweed used, what stage in its growth or lifespan the seaweed is at when harvested, and how it is processed.
To make Carrageen, seaweed is harvested, then inspected, then cleaned, then processed. The Carrageen can be extracted boiling, or through alcohol or various alkalis.
Carrageen used to just come from Irish Moss seaweed (L. Chondrus crispus), but now it is extracted from other seaweeds as well, even tropical ones, such as the species known as Kappaphycus alverezii and Eucheuma denticulatum.
80% of the world's supply of Carrageen is now (2006) made in the Philippines, from seaweeds called Cottonii (Eucheuma cottonii, aka Kappaphycus cottonii) and Spinosum (Eucheuma spinosum.) Spinosa is also sold in markets there as "guzo" for use partly as a salad vegetable. In the Philippines, the seaweed is cultivated on lines strung between floats. It can be harvested after 3 months. Harvesting is largely done by families and individuals.
There are three main categories of Carrageen:
Kappa CarrageenKappa Carrageen is produced from the seaweed known as Kappaphycus cottonii. It is used to make strong, rigid, clear gels. It is soluble in hot water, and forms a gel when cooling. It doesn't, though, stand up well to freezing and thawing.
Iota CarrageenIota Carrageen is produced from the seaweed known as Eucheuma spinosum. This seaweed grows at the top of the ocean, growing from the surface downwards about 7 feet (2 metres.) It is used to make soft gels. It is soluble in hot water, but needs calcium to interact with to gel. It holds water well, and stands up well to freezing and thawing.
Lambda CarrageenLambda Carrageen is produced from Gigartina seaweed (during its spore-producing stage), and others. It cannot form gels, it just thickens, but it thickens better than the other two mentioned above. It is soluble in hot and cold water, but needs protein to interact with. It doesn't absorb water. It is used in dairy products.
There is evidence that a version of Carrageen, "poligeenan", which is made for industrial purposes would be unsafe in food. It is not, however, certified or used in food, particularly because it has none of the properties of carrageen (such as thickening) that would make it even remotely useful to the food industry.
Carrageen also meets requirements to be kosher (parve.)
. European Commission: Health & Consumer Protection Directorate-General. Scientific Committee on Food on Carrageenan. Scientific Committee on Food SCF/CS/ADD/EMU/199 Final. 21 February 2003.
The English word comes from the Irish town of Carragheen. People there boiled Irish moss to obtain the gelling agent out of it for use in cooking.
The two earliest commercial producers of Carrageen were located in Maine and in Denmark.
In Irish, the moss is called "carraigín."