Chain conformation, rheological and charge properties of fucoidan extracted from sea cucumber Thelenota ananas: A semi-flexible coil negative polyelectrolyte.

As a bioactive and functional polysaccharide, sea cucumber fucoidan has received increasing attention. Chain conformation and physicochemical properties of fucoidan extracted from Thelenota ananas (Ta-FUC) was investigated by utilizing HPSEC-MALLS-Visc-RI, microelectrophoresis and steady shear measurements. The conformation parameter α s (0.61 ± 0.02), the Mark-Houwink-Kuhn-Sakurada exponent α η (0.92 ± 0.01), α h (0.64 ± 0.01) and the Smidsrød-Haug stiffness parameter B (0.036 ± 0.010) consistently manifested that Ta-FUC adopted a semi-flexible coil conformation in NaCl solution. Based on a wormlike cylinder model, stiffness parameters, including persistence length q (13.27 ± 0.80 nm) and cylinder diameter d (0.79 nm), were calculated. This polysaccharide demonstrated shear-thinning rheological behaviour, and critical concentration from dilute to semidilute concentration regime was determined as 3.6 mg/ml. Ta-FUC exhibited as a negative polyelectrolyte in wide pH and ionic strength ranges. These molecular characteristics and physicochemical properties would facilitate further application of Ta-FUC as a functional ingredient in food. [ABSTRACT FROM AUTHOR]