Kappaphycus alvarezii gelling, thickening, and stabilizing agents, especially in food products such as frozen desserts, chocolate milk, cottage cheese, whipped cream, instant products, yogurt, jellies, pet foods, and sauces. Aside from these functions, carrageenans are used in pharmaceutical formulations, cosmetics, and industrial applications such as mining. Carrageenan is extracted from this seaweed in two ways. In native extraction, the seaweed is made into an aqueous solution, and the residue is filtered, leaving nearly pure carrageenan. The alkaline-modified method is less expensive and easier. The seaweed is mixed in an alkali solution, leaving a mixture of carrageenan and cellulose that can be sold
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