Antioxidant activities of crude extracts of fucoidan extracted from Sargassum glaucescens by a compressional-puffing-hydrothermal extraction process

•A novel CPHE process for extraction of fucoidan from brown algae was developed.•The CPHE process provided operational, economic, and environmental advantages.•The crude extracts of fucoidan extracted by the CPHE process showed potential for use as natural antioxidant agents. Fucoidan, a multifunctional marine polymer, is normally extracted from brown algae via extensive use of acid, solvent or high temperature water and a long reaction time. In present study, we developed a novel compressional-puffing-hydrothermal extraction (CPHE) process which primarily decomposes the cellular structure of algae and facilitates the release of fucoidan by hot water extraction. The CPHE process provides a number of advantages including simple procedure, reactant-saving, reduced pollution, and feasibility for continuous production. Sargassum glaucescens (SG) was utilized in this study, and the maximum extraction yield of polysaccharide was approximately 9.83±0.11% (SG4). Thin layer chromatography (TLC), Fourier transform infrared (FTIR) analysis, and measurements of monosaccharide composition, fucose, sulfate, and uronic acid contents revealed that the extracted polysaccharide showed characteristics of fucoidan. All extracts exhibited antioxidant activities, and thus, further exploration of these extracts as potential natural and safe antioxidant agents is warranted.