Carrageenan
Carrageenans or carrageenins (/ˌkærəˈɡiːnənz/ KARR-ə-GHEE-nənz; from Irish carraigín 'little rock') are a family of natural linear sulfated polysaccharides.
Carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble animal glycosaminoglycans (GAGs).
[2] A common seaweed used for manufacturing the hydrophilic colloids to produce carrageenan is Chondrus crispus (Irish moss), which is a dark red, parsley-like alga that grows attached to rocks.
[7] No clinical evidence establishes carrageenan as an unsafe food ingredient, mainly because its fate after digestion is inadequately determined.
[12][13] In parts of Scotland and Ireland, where it is known by a variety of local and native names, Chondrus crispus is boiled in milk and strained, before sugar and other flavourings such as vanilla, cinnamon, brandy, or whisky are added.
(today one of the main cultivated sources of carrageenan), known as gusô or tambalang in the Visayan languages, has also been traditionally used as food in the Philippines.
The seaweed is normally grown on nylon lines strung between bamboo floats, and it is harvested after three months or so, when each plant weighs approximately 1 kg (2.2 lb).
After treatment with hot alkali solution (e.g., 5–8% potassium hydroxide), the cellulose is removed from the carrageenan by centrifugation and filtration.
The weed is then washed to remove salt and sand, and then cooked in hot alkali to increase the gel strength.
[17] The essential difference in the refining process is that the carrageenan is first dissolved and filtered to remove cell wall debris.
[18] A hybrid technology in which seaweed is treated heterogeneously as in the semirefined process exists, but alcohol or high salt levels are used to inhibit dissolution.
[11] Refined carrageenan has a 2% maximum for acid-insoluble material and is produced by alcohol precipitation or potassium chloride gel press process.
[30] On April 4, 2018, the Agricultural Marketing Service (AMS) (USDA) announced the renewal of carrageenan on the National List, allowing its continued use in food products.
[31]The use of carrageenan in infant formula is prohibited in the EU for precautionary reasons, but is permitted in other food items.
[8][35] Research has been done into the role of carrageenan in various forms of inflammatory bowel disease and allergic reactions,[36][37] with much of the concern centered around the specific α-D-Gal-(1→3)-D-Gal glycosidic bond present in carrageenan, which interacts as an epitope with TLR4 in cultivated human epithelial cells of the mucous membrane;[35][37] this is linked to alpha-gal syndrome.
