Carrageenan

Carrageenan (also: Carragaheen, carrageenan or carrageenan, carrageenan English ) is a collective term for a group of long-chain carbohydrates ( polysaccharides), which occur as the similar substances agar-agar or alginate in the cells of various species of red algae. It is linear, anionic hydrocolloids. Depending on the chemical structure of various Carrageentypen be distinguished, which have different properties. These different types are in the first place by the proportion of galactose and 3,6-anhydrogalactose and about the number of sulfate groups. Of commercial importance are κ -, ι - and λ - carrageenan in the first place.

Production

For the production of carrageenan from red algae, the algae are washed and boiled in an alkaline solution. This process can take up to 48 hours, as this still certain precursors of carrageenan ( μ - and ν - carrageenan ) are converted to κ - and ι - carrageenan, thus reinforcing the functional effect. Then the solution is filtered to remove the remaining components of algae. To obtain the carrageenan from the solution, the carrageenan is precipitated either by alcohol or gelled by means of potassium chloride and then pressed. The carrageenan obtained is then dried and milled. As algae sources found mainly Chondrus, Eucheuma and Gigartinaspezies use. Much of the algae is now being won in algae farms in the Philippines, here, see especially the species Eucheuma spinosum and Eucheuma cottonii use because of these kinds of high purity Carrageentypen can be obtained.

Carrageentypen

Even if only κ -, ι and λ - carrageenan are of commercial interest, other types are present in the seaweed. Two - in addition to the commercially occurring -. Types are μ and ν - carrageenan, which may be considered as precursors to κ - carrageenan and ι and converted largely in these types in the extraction The percentage of carrageenan in the final Carrageentypen therefore depends both on the used type of algae, as well as the manufacturing process. For this reason, it never is in commercial carrageenans by absolutely pure individual types.

κ - carrageenan

κ - carrageenan gelled with potassium ions to form a solid and brittle, and with calcium ions to form a solid, elastic and synäresearmen gel. It is only soluble as the sodium salt in cold water. As a calcium or potassium salt of significantly higher temperatures are required to fully dissolve the carrageenan. On cooling the carrageenan is from the coiled shape in a helix structure over. On further cooling occurs at the interaction with the calcium or potassium ions to agglomeration of the helices, and thus for forming a network. κ - Carrageenan also has a high Milchreaktivität. For this reason, small amounts of carrageenan already sufficient to stabilize chocolate / cocoa drinks and to prevent sales of cocoa particles. This Milchreaktivität is due to interactions of the negatively charged hydrocolloid with certain parts of the casein.

Below the isoelectric point of the protein to its charge altered and the carrageenan is precipitated from the protein. For this reason you find yourself virtually no acidic dairy products, which are stabilized with carrageenan. In addition to the interactions with milk protein κ - carrageenan shows synergism with tara gum, locust bean gum and konjac gum. This leads generally to an increase in the gel structure and melting and Gelpunkten shifted to higher temperatures.

ι - carrageenan

ι - carrageenan gels with calcium and is often used for dressings or softer gels. Also ι - carrageenan is just as cold-soluble sodium salt and required as calcium or potassium form also higher temperatures. During the cooling of the hot Carrageenlösung it comes (similar to the κ - carrageenan ) for helix formation, these helices form calcium bridges over a network.

λ - carrageenan

λ - carrageenan does not form gels and is both cold and hot highly soluble. This Carrageenan is widely used in the field of instant products where no heating is to take place. λ - carrageenan does not form helical structures upon cooling.

Applications

In the food industry as a gelling agent carrageenan is for slimming and light products and in meat products ( eg sausage), and used as a thickener in the mixed cold jams, baby food, dairy products, milk shakes, ice cream and desserts. With the help of carrageenan also cloudiness in wines can be eliminated. In the EU it is approved as a food additive with the E number 407. Carrageenan is also used in the cosmetics industry ( toothpaste).

The thickening agent carrageenan (E 407) is also approved by the European Organic Regulation for organic food.

Health aspects

Carrageenan was rated by the independent Expert Committee of FAO / WHO and by the U.S. FDA as harmless. Meanwhile, however, an allowable daily dose of 75 mg per kg of body weight per day has been set.

In animals, ulceration and changes in the immune system have been observed with degraded carrageenan. If carrageenan is heated at high temperatures and at low pH, produced degraded carrageenan ( Polygeenan ). The longer the heating, the more the carrageenan is reduced. In response to the study, the EU has expanded its recommendation to carrageenan consumption of up to 0-75 mg per kg of body weight per day by adding that in foods no more than 5 % of the molecular weight of the carrageenan should be below 50 kDa. In a study carried out in 2001 by 29 carrageenans for the food industry, the average molar mass was 453-652 kDa, and Polygeenan could not be detected ( Uno et al., 2001).

There are claims that carrageenan hinders the absorption of minerals such as potassium and can cause allergies.

A study from 2006 shows a significant, yet not fully explained antiviral activity against human papillomavirus (HPV ) that can cause cervical cancer.

Further show some work that has influence on the activity of carrageenan macrophages.