Conformational and physicochemical properties of fucosylated chondroitin sulfate from sea cucumber Apostichopus japonicus

• Fucosylated chondroitin sulfate from Sea cucumber (Aj-fCS) was prepared and investigated.
• Chain conformation was analyzed by HPSEC-MALLS-Visc-RI and worm-like cylinder model.
• Aj-fCS exhibited a random coil chain conformation in solution.
• Aj-fCS showed a shear thinning behavior and a good thermostability.
• Aj-fCS possessed negative charge in wide range of pH and ionic strength.

This study aimed at investigating the chain conformation and physicochemical properties of fucosylated chondroitin sulfate extracted from sea cucumber Apostichopus japonicas (Aj-fCS). By using HPSEC-MALLS-Visc-RI, Mw, z1/2, Rh and [η] for Aj-fCS were determined as 58.0 ± 4.4 kDa, 21.8 ± 1.3 nm, 12.5 ± 1.3 nm and 27.8 ± 0.5 mL/g respectively. Conformation parameter αs derived from the relationship of Mw-z1/2 (0.39) and structure-sensitive parameter ρ (1.74) consistently indicated that Aj-fCS adopted a random coil conformation in solution, which was also supported by atomic force microscopy. Stiffness parameters of Aj-fCS chains including q (2.72 nm), d (1.03 nm) and C∞ (5.28) were furthermore deduced from the worm-like cylinder model. Aj-fCS demonstrated a shear-thinning rheological behavior, relatively low apparent viscosity, negative charge in wide pH and ionic strength ranges, and favorable thermostability. These results have important implications for designing and fabricating functional foods or drugs based on Aj-fCS.