Carrageenan

Function

Carrageenan is a geling agent extracted from many species of red algae.  The texture of the carrageenan gels varies form simple thickening to firm gel.  For this reason, carrageenans are used in molecular gatronomy in a vast array of hot or cold dishes of jelly or mousse.

Origin

Carrageenan is a natural polymer fibre extracted from red algae. It is what gives these algae flexibility and strength. It consists of carbohydrates and ions of potassium and calcium, which are responsible for its gelling properties.

The first documentation on the use of carrageenan comes from Ireland and dates back to 1810, when the alga was prescribed, boiled in milk, against respiratory problems. Perhaps the name derives its origin from the Gaelic term "carraigín" meaning "moss" in reference to the algae from which it is extracted. From Ireland, the use of carrageenan reached New England with the immigration in the eighteenth and nineteenth century. The industry developed greatly during the Second World War.

Nowadays, the use of carrageenan is so widespread in the food industry that it has become the most widely used algae extracted additive. Its popularity has significantly contributed to the development of the culture of two species of red algae: Eucheuma denticulatum and Kappaphycus alvarezii.

Properties

There are many types of carrageenan, which are distinguished by their properties and their chemical structure. The types of carrageenan used by the food industry are usually composed of a mixture of various species of red algae according to concentrations that can meet specific needs. These commercial mixtures are called iota, kappa and lambda.

The iota carrageenan is a gelling agent that, with the presence of calcium, produces especially flexible and elastic gels. These gels are clear and resistant to temperature variations. It is not soluble in cold water. A solution of iota carrageenan must therefore be heated to over 60°C (140°F) to allow dissolving. The gelling will take place during cooling period, reacting with the calcium or potassium.

The kappa carrageenan is also a gelling agent. It allows the formation of very firm and elastic gels in the presence of potassium. In the presence of calcium, the gels will take on a rather stiff and brittle texture. The kappa carrageenan is insoluble in cold water. A solution of kappa carrageenan must be heated to over 60°C (140°F) to allow dissolving. Gelling will take place at time of cooling, reacting with the calcium or the potassium. The gels containing kappa are slightly opaque but can be thinned by adding sugar. They are thermo-reversible, that is to say, they melt when heated and return to gel during cooling.

The lambda carrageenan is generally used to increase the viscosity of preparations and cannot be used to form gels.

Industry applications

A large proportion of the production of carrageenan is directed toward the food industry and, more specifically, to the dairy processing industry, where it often acts as an anti-settling agent and stabilizer. For example, carrageenan is used to prevent the separation of proteins and thus maintains the uniformity of products like cottage cheese and ice cream. In chocolate milk, it is what keeps cocoa particles in suspension.

Carrageenan also serves as anti-settling agent in light salad dressings, in addition to giving a similar in-mouth feeling to that of the original product. It plays a similar role in light mayonnaise.

Carrageenan is often used in processed meats, to facilitate the retention of brine in the product. This property of fluid retention is exploited in healthy foods, where carrageenan gives a juicy texture to lightened meat despite the absence of fat.

Creative cooking applications

Carrageenan can form multiple gels in a wide range of textures, from very soft to very firm, and from elastic to brittle. These gels can then be served hot or cold.

Healthy cooking applications

Carrageenan can be used to create flans without eggs, for example. Different combinations of additives containing carrageenan can also be used as alternatives to animal gelatin.

Tips and tricks

To dissolve carrageenan powder, a hand blender is recommended although it is possible to avoid lumps with a wire whisk by making sure the carrageenan powder is dispensed lightly and gradually into the mixture. Since carrageenan is difficult to dissolve in cold water, the additive can first be dissolved in a small amount of boiling water and then be poured into the final preparation.