Structural variability and rheological properties of furcellaran

• Published in: Food hydrocolloids 2021-02, Vol.111, p.106227, Article 106227
• Main Authors: Saluri, Mihkel, Kaljuvee, Kadri-Liis, Paalme, Tiina, Reile, Indrek, Tuvikene, Rando
• Format: Article
• Language: English
• Subjects: 1H NMR; Furcellaran; Rheometry; Size exclusion chromatography; β-carrageenan; κ-carrageenan
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2020.106227

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. [Display omitted] •The analysed furcellaran samples had a sulphate group for every 3.9 monomers.•The estimated peak average molecular weights were above 1200 kDa.•Furcellaran gels (1.5% w/w) exhibited a maximum degree hysteresis of 31 °C.