Deeply Shaped: When Eutectic Solvents Meet Brown Seaweed

Brown seaweed is a rich natural resource, yet much of it goes underused because traditional processing targets one product and discards the rest. This thesis explores deep eutectic solvents (DES) as an alternative. DES are made by mixing ingredients that are solid on their own, often from natural sources, which turn into a liquid when combined in the right proportions. Several DES mixtures were tested to extract alginate, a thickener used in food; fucoxanthin, an orange pigment; and later fucoidan, a carbohydrate with several potential health benefits. Besides extracting well, DES changed the products: alginate was more viscous, and fucoxanthin even turned blue, a rarely observed form. Different ways of recovering several products from the same seaweed were designed, showing that extraction order matters. Cost and environmental assessments showed that industrial use requires solvent recycling, multiple products, and products with clear advantages over conventional ones. Overall, DES could become tools not only to extract, but also to tailor product properties.