Carrageenan is a family of linear sulfated polysaccharides extracted from red edible seaweeds such as Chondrus crispus. It is widely used in the food industry as a thickening, gelling, and stabilizing agent in products like dairy, meats, and desserts. There are three main commercial types (kappa, iota, lambda) differing in sulfation patterns and gel properties. Chemically, it consists of alternating D-galactose and 3,6-anhydro-D-galactose units with varying sulfate esters. Its ability to form thermoreversible gels and increase viscosity makes it valuable for texture modification. It is approved as food additive E407 in the EU and has GRAS status from the FDA.