carrageenans

Carrageenans are sulfated polysaccharides derived from red edible seaweeds. They consist of repeating galactose units with varying degrees of ester sulfate and the presence of 3,6-anhydrogalactose. The main commercial forms are kappa, iota, and lambda carrageenan, distinguished by sulfate content and gelling behavior. Kappa carrageenan carries about one sulfate per disaccharide and forms strong, rigid, thermally reversible gels in the presence of potassium ions; iota carrageenan has about two sulfates and forms soft, elastic gels with calcium; lambda carrageenan carries three or more sulfates and does not gel but acts as a thickener.

In food systems, carrageenans are used as thickening, stabilizing, and gelling agents. They help regulate texture, prevent whey separation in dairy products, and provide viscosity in vegan milks, processed meats, sauces, and desserts. In dairy, carrageenan can improve mouthfeel and stabilize dispersed phases. They are also used in cosmetics, toothpaste, and other personal care products as thickeners and stabilizers.

Extraction typically involves alkaline treatment of the seaweed to solubilize the polysaccharide, followed by precipitation, purification, and drying. Raw material sources include Chondrus crispus (Irish moss), Gigartina species, Eucheuma cottonii, and Hypnea species; large-scale production relies on farmed red seaweeds.

Safety and regulation: Carrageenan is approved as a food additive in many jurisdictions (E407). Degraded carrageenan (poligeenan) is not permitted in foods. Regulatory reviews by agencies such as the U.S. FDA and EFSA have concluded that undegraded carrageenan is safe at approved uses, while some studies have linked higher intakes to gastrointestinal symptoms in sensitive individuals. Environmental and sustainability issues include seaweed farming practices and supply variability.