Sulfated polysaccharides classification

Classification Sulfated polysaccharide Definition Hydrocolloid obtained from various members of the Gigartinaceae or Solieriaceae families of the red seaweed, Rhodophyceae consists of sulfite esters of galactose and 3,6-an hydrogalactose copolymers Properties Yel. wh. powd., odorless, tasteless sol. in hot water, hot cone. NaCI sol n. insol. in oils and org. soivs. 

Classification of carrageenans takes into account the sulfation pattern of the A-unit the K-family comprises 4-sulfated polysaccharides, while the. -family includes those with 2-sulfation (Fig. 1). Less important are the P-family, in which the A-unit is not sulfated and the co-family with sulfation on C-6 of this unit. 

Polysaccharides are differentially stable to cold dilute alkali, which facilitates classification as alkali-stable and alkali-sensitive (Reeves and Blouin, 1957). High concentrations of alkali swell fibrils, shift conformation, and depolymerize the primary structure. The 1,4-(3 bonds are more alkali-resistant than the 1,4-a bonds. Nonreducing glycosides are more stable than reducing glycosides. Ester and sulfate groups are easily hydrolyzed. 

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