Impact of sulfate groups on the physicochemical properties of Fucoidan from <i>Lessonia trabeculata</i>

BACKGROUND: The bioactivities of polysaccharides are closely associated with their molecular architecture, where factors including molecular weight, monosaccharide composition, sulfate content and other structural characteristics significantly affect their potential applications. Lessonia trabeculata is an important economic brown alga. The structure of fucoidan extracted from L. trabeculata (LTF) and its potential applications in the food industry warrant further investigation. RESULTS: Fucoidan extracted and purified from L. trabeculata was a sulfated heteropolysaccharide with a molecular weight of 33.4 kDa and a sulfate content of 34.7%. The structure of LTF was characterized based on monosaccharide composition, methylation analysis and nuclear magnetic resonance spectroscopy. The backbone of LTF was composed of →4)-β-d-Xylp-(1→3)-β-l-Fucp-(1→residues, and alternating →2)-β-l-Fucp-(1→3)-β-l-Fucp-(1→, in which the β-l-Fucp residues were either 4-O-sulfated or substituted with α-d-Manp side chains. Additionally, an alternating →3)-α-l-Fucp-(1→4)-α-l-Fucp (2-O-sulfated)-(1→ sequence existed as a secondary chain). In addition, the present study found that native LTF exhibited superior moisture absorption, moisture retention, oil-holding, water-holding capacities and emulsifying activity relative to deS-LTF. Overall, our results indicated that sulfate groups in LTF significantly affect its functional properties. CONCLUSION: This study demonstrates the potential of LTF as a promising emulsifier in the food and cosmetic industries. These findings provide a theoretical basis for the practical application of LTF in related fields. © 2026 Society of Chemical Industry.