Carrageenan only the lambda form (and the sodium salts of the other two) are soluble. When used in food products, carrageenan has the EU additive E numbers E407 or E407a when present as "processed eucheuma seaweed". Technically carrageenan is considered a dietary fibre. 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. The end-product is a kind of jelly similar to panna cotta, tapioca, or blancmange. Although carrageenans were introduced
Red algae contain the sulfated polysaccharide carrageenan in the amorphous sections of their cell walls, although red algae from the genus Porphyra contain porphyran. They also produce a specific type of tannin called phlorotannins, but in lower amount than brown algae do. Complete genome sequences are only available for 6 species of red algae, including 4 published in 2013. One of the oldest fossils identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon. "Bangiomorpha pubescens", a multicellular fossil from arctic Canada, strongly resembles the modern red alga "Bangia" despite occurring in rocks dating