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Carrageenans or carrageenins ( from Irish ''carraigín'', "little rock") are a family of linear sulphated polysaccharides that are extracted from red edible seaweeds. They are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. There are three main varieties of carrageenan, which differ in their degree of sulphation. Kappa-carrageenan has one sulphate group per disaccharide. Iota-carrageenan has two sulphates per disaccharide. Lambda carrageenan has three sulphates per disaccharide. Gelatinous extracts of the ''Chondrus crispus'' (Irish Moss) seaweed have been used as food additives since approximately the 15th century.〔(FAO Agar and Carrageenan Manual ). Fao.org (1965-01-01). Retrieved on 2011-12-10.〕 Carrageenan is a vegetarian and vegan alternative to gelatin in some applications or may be used to replace gelatin in confectionery. == Properties == Carrageenans are large, highly flexible molecules that curl forming helical structures. This gives them the ability to form a variety of different gels at room temperature. They are widely used in the food and other industries as thickening and stabilizing agents. All carrageenans are high-molecular-weight polysaccharides made up of repeating galactose units and 3,6 anhydrogalactose (3,6-AG), both sulfated and nonsulfated. The units are joined by alternating α-1,3 and β-1,4 glycosidic linkages. There are three main commercial classes of carrageenan: * Kappa forms strong, rigid gels in the presence of potassium ions; it reacts with dairy proteins. It is sourced mainly from ''Kappaphycus alvarezii''.〔(), FAO Fisheries Technical Paper No. 441〕 * Iota forms soft gels in the presence of calcium ions. It is produced mainly from ''Eucheuma denticulatum''.〔 * Lambda does not gel, and is used to thicken dairy products. The primary differences that influence the properties of kappa, iota, and lambda carrageenan are the number and position of the ester sulfate groups on the repeating galactose units. Higher levels of ester sulfate lower the solubility temperature of the carrageenan and produce lower strength gels, or contribute to gel inhibition (lambda carrageenan). Many red algal species produce different types of carrageenans during their developmental history. For instance, the genus ''Gigartina'' produces mainly kappa carrageenans during its gametophytic stage, and lambda carrageenans during its sporophytic stage. All are soluble in hot water, but in cold water, 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-number E407 or E407a when present as "processed eucheuma seaweed".〔 Technically carrageenan is considered a dietary fibre.〔http://www.marine-science.co.jp/english/goods/carra.html, Marine Science Co. Ltd.〕 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 pannacotta, tapioca, or blancmange. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「carrageenan」の詳細全文を読む スポンサード リンク
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