Characterization of ulvan extracts to assess the effect of different steps in the extraction procedure

► A sulfated polysaccharide, ulvan, was extracted from green algae and purified. ► The composition were assessed by multiple and complementary methodologies. ► Acid methanolysis was improved to obtain the maximum yield on released monosaccharides. ► Ulvan is highly sulfated and composed by rhamnose, xylose, glucuronic and iduronic acids. ► The polysaccharide is not affected by the different steps in the extraction procedure.