Kappa carrageenan from the red alga Kappaphycus striatus cultivated at Vanphong Bay, Vietnam: physicochemical properties and structure

Abstract

The red alga Kappaphycus striatus “sacol” brown strain is an economically important species and extensively cultivated at Vanphong Bay, Vietnam. To elucidate the carrageenan quality, the chemical profile of the alkali-modified carrageenan from this alga was investigated by FT-IR, 1H and 13C NMR spectroscopies, and methods of analysis. The structural components of the polysaccharide mainly consisted of 3,6-anhydro-α-D-galactose and β-D-galactose-4-sulfate. FT-IR and 1H and 13C NMR spectra indicated that the polysaccharide was composed predominantly of kappa carrageenan with a small amount of iota carrageenan and 6-O-methylated carrageenan. The red alga K. striatus\xa0is good source of carrageenan for application in food or medicine.