Fucoidans is extracted from Undaria pinnatifida by using CaCl2 extraction method. Sea weed algae sporophyll shows significantly high fucoidan (25.4–26.3%) to (57.3–69.9%) from July to September. Sulphate content in the extracted fucoidan increased more than twice within the same period, while fucose content remained constant. Most of the fractions contain fucoidan mainly contained fucose as the primary sugar component followed by galactose, with xylose, glucose and mannose as minor constituents
Water extraction method is good for fucoidan extraction and you will be getting good quality and purity of fucoidan after removing the alginic acid from extract and final washing with ethanol.