Carrageenan is a family of linear sulfated polysaccharides extracted from red edible seaweeds, primarily Chondrus crispus and Eucheuma species. It functions as a hydrocolloid with gelling, thickening, and stabilizing properties in food applications such as dairy products, meats, and desserts. Three main types exist: kappa (strong gels with potassium), iota (elastic gels with calcium), and lambda (thickener without gelling). Chemically composed of alternating galactose and 3,6-anhydrogalactose units with sulfate esters, it is highly soluble in hot water forming viscous solutions. It is approved as a food additive (E407) and considered GRAS by regulatory bodies. No significant toxicity at typical dietary levels; potential gastrointestinal effects only at very high doses in animal studies.