Physicochemical characterization of carrageenan from Gigartina teedii (Rooth) Lamouroux (Gigartinales, Rhodophyta)

The phycocolloids of female gametophytes of Gigartina teedii (Roth) Lamouroux harvested in Roscoff (Brittany, France) are a hybrid carrageenan resulting from juxtaposition of fragments of kappa-, iota- and nu-carrageenan. They represent 70% of the dry matter of the alga in summer. After alkaline transformation the proportion of iota-carrageenan increased to 76%, demonstrating the presence of nu-carrageenan. Absence of mu-carrageenan, the precursor of kappa-carrageenan, suggests that iota-carrageenan is desulfated enzymically to kappa-carrageenan.