Laminarin standard

For this study, three fucoidan polymers were extracted from Fucus vesiculosus (Biocean, Roscoff, France) using microwave-assisted extraction. The extraction procedure was adapted and modified for microwave-assisted extraction from the method provided by Fletcher et al. (2017) (link) [45] (link). Extraction was carried out by microwaving at 120°C for 30 minutes, using demineralized water, 10 mM H 2 SO 4 , and 100 mM HCl. Once cooled, the extracts were neutralized with 1 M NaOH. For alginate precipitation, a solution of 35% calcium chloride was added to each extract for a total concentration of 1%. The extracts were then centrifuged (4°C, 30 min) and the supernatant was recovered. Ethanol was added for a concentration of 40% v/v ethanol to precipitate laminarin. The extracts were centrifuged, and the supernatant was recovered. Ethanol was added to give a final concentration of 70% v/v ethanol to precipitate crude fucoidan. The extracts were centrifuged and the crude fucoidan pellet was washed with ethanol and acetone and left to dry to a constant weight. The crude Fucoidan extracts were solubilized in water, dialyzed and lyophilized prior to Raman and IR analysis. For more details, see reference [46] . A fucoidan and a laminarin standard (Sigma Aldrich) were solubilized in demineralized water and used as structural references.