EFFECT OF SOLVENT TYPE AND EXTRACTION TEMPERATURE ON SULFATE AND URONIC ACID CONTENT IN Eucheuma cottonii FUCOIDAN

Fucoidan, a sulfated polysaccharide typically obtained from seaweed, has its composition affected by various factors, including species, habitat conditions, seasonal variations, extraction techniques, and harvest maturity. The seaweed species Eucheuma cottonii from the Banggai Islands is a rich source of bioactive polysaccharides, including uronic acid, laminarin, and fucoidan. Fucoidan predominantly contains fucose as its main component, sulfate, and small amounts of monosaccharides like galactose and glucose. The chemical properties of fucoidan, such as sulfate and uronic acid levels, are critical for determining its functional activity. This study investigated the influence of two extraction parameters: type of solvent (HCl, CaCl₂, ethanol, EDTA, H₂O) and extraction temperature (40, 50, 60, 70, and 80℃). These variations were applied to assess their effects on the sulfate and uronic acid contents of fucoidan extracted from Eucheuma cottonii. The results showed that the EDTA solvent was the most effective for fucoidan extraction, yielding the highest sulfate content (11.22%) at 80℃. In contrast, the HCl solvent resulted in the lowest sulfate content (4.54%). Regarding uronic acid content, the highest value (4.55%) was observed at 80℃ with the HCl solvent, while the lowest (1.40%) was obtained at 40℃ with the EDTA solvent. These findings highlighted the significant impact of solvent type and extraction temperature on the chemical composition of fucoidan, influencing its bioactivity and applications. This study demonstrated that EDTA was an excellent solvent for fucoidan extraction, particularly at 80℃, maximizing sulfate content and providing insights for optimizing fucoidan extraction to enhance its functional and bioactive properties.