LAUSR

Abstract Furcellaran (β/κ-carrageenan hybrid) samples were extracted from the drifting (n = 36) and attached (n = 46) forms of red algae Furcellaria lumbricalis, collected from the Estonian waters in the Baltic Sea. The extracted polysaccharides were characterised with 1H NMR and size-exclusion chromatography. Additionally, the gelling points, storage moduli and melting points of furcellaran samples were determined with a dynamic rheometer. Results showed that the extracted furcellaran samples contained a sulphate ester group per every 3.3 to 4.5 monosaccharide residues. On average, the furcellarans had a sulphate group for every 3.9 monomers, indicating nearly equimolar amounts of β- and κ-carrageenans in the tested polysaccharide samples. The estimated peak average molecular weights of the samples were higher for the furcellarans extracted from attached specimens. Furcellaran gels exhibited a three-time decrease in storage moduli (from ~30000 Pa to ~9300 Pa) when KCl concentrations were reduced from 40 mM to 10 mM. Also, on average, the furcellaran gels (1.5% w/w) in 40 mM KCl solutions exhibited a degree hysteresis of 31 °C.