Structural Characterization and Rheological and Antioxidant Properties of Novel Polysaccharide from Calcareous Red Seaweed

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and H-1/C-13 NMR) techniques. Results showed that JASX was constituted by repeating units of (-> 3)-beta-d-Galp-(1,4)-3,6-alpha-l-AnGalp-(1 ->)(n) and (-> 3)-beta-d-Galp-(1,4)-alpha-l-Galp-(1 ->)(n) substituted on O-2 and O-3 of the alpha-(1,4)-l-Galp units by methoxy and/or sulfate groups but also on O-6 of the beta-(1,3)-d-Galp mainly by beta-xylosyl side chains and less by methoxy and/or sulfate groups. The M-w, M-n, D, [eta] and C* of JASX were respectively 600 and 160 kDa, 3.7, 102 mL.g(-1) and 7.0 g.L-1. JASX exhibited pseudoplastic behavior influenced by temperature and monovalent salts and highly correlated to the power-law model and the Arrhenius relationship. JASX presented thixotropic characteristics, a gel-like viscoelastic behavior and a great viscoelasticity character. JASX showed important antioxidant activities, outlining its potential as a natural additive to produce functional foods.