FINE CHEMICAL STRUCTURE OF CARRAGEENAN FROM THE COMMERCIALLY CULTIVATED KAPPAPHYCUS STRIATUM (SACOL VARIETY) (SOLIERIACEAE, GIGARTINALES, RHODOPHYTA)1

The polysaccharide extracted from Kappaphycus striatum (Schmitz) Doty (sacol variety), a recently farmed eucheumoid seaweed, was characterized by Fourier transform infrared and NMR spectroscopy. The extract is composed mainly of 3‐linked β‐d‐galactopyranosyl‐4‐sulfate residues alternating with 4‐linked 3,6‐anhydro‐α‐d‐galactopyranosyl residues (κ‐carrageenan). Minor components include 3,6‐anhydrogalactopyranosyl‐2‐sulfate residues (ι‐carrageenan) and 6‐O‐methylgalactopyranosyl‐4‐sulfate residues (methylated carrageenan). The substitution pattern of carrageenan in the tribe Eucheumatoideae and the family Solieriaceae is revisited in terms of chemotaxonomic affiliation.