Simultaneous Extraction and Depolymerization of Fucoidan from Sargassum muticum in Aqueous Media

The biomass components of the invasive seaweedSargassum muticumwerefractionatedto allow theirseparatevalorization.S. muticum(Sm) and the solid residueremaining after alginate extraction of this seaweed (AESm) were processed with hot,compressed water (hydrothermal processing) to assess the effects of temperature onfucoidan solubilization.Fucose-containing oligosaccharides were identified as reactionproducts. Operating under optimal conditions (170°C), up to 62 and 85 wt% of the drymass of Sm and AESm were solubilized, respectively. The reaction media were subjectedto precipitation, nanofiltration and freeze-drying. The dried products contained 50%and 85% of the fucoidan present in Sm and AESm, respectively; together with othercomponents such as phenolics and inorganic components. The saccharidic fraction,accounting forup to 35% of the dried extracts, contained fucose as the main sugar, andalso galactose, xylose, glucose and mannose. The concentrates were characterized forantioxidant activity using the TEAC assay.