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A novel sulfated xylogalactan-rich fraction (JSP for J. adhaerens Sulfated Polysaccharide) was extracted from the red Tunisian seaweed Jania adhaerens. JSP was purified using an alcoholic precipitation process and characterized by Attenuated Total Reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), high-pressure size exclusion chromatography (HPSEC) with a multi-angle laser light scattering (MALLS), gas chromatography coupled to mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR, 1D and 2D). JSP was then evaluated regarding its physicochemical and rheological properties. Results showed that JSP was mainly composed of an agar-like xylogalactan sharing the general characteristics of corallinans. The structure of JSP was mainly composed of agaran disaccharidic repeating units (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)n and (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n, mainly substituted on O-6 of (1,3)-β-d-Galp residues by β-xylosyl side chains, and less with sulfate or methoxy groups. (1,4)-α-l-Galp residues were also substituted by methoxy and/or sulfate groups in the O-2 and O-3 positions. Mass-average and number-average molecular masses (Mw) and (Mn), intrinsic viscosity ([η]) and hydrodynamic radius (Rh) for JSP were, respectively, 8.0 × 105 g/mol, 1.0 × 105 g/mol, 76 mL/g and 16.8 nm, showing a flexible random coil conformation in solution. The critical overlap concentration C* of JSP was evaluated at 7.5 g/L using the Williamson model. In the semi-diluted regime, JSP solutions displayed a shear-thinning behavior with a great viscoelasticity character influenced by temperature and monovalent salts. The flow characteristics of JSP were described by the Ostwald model. [ABSTRACT FROM AUTHOR]

With the aim to optimize the production of exopolysaccharide (EPS) by Porphyridium marinum , cultures in photobioreactors were conducted on a modified Provasoli medium (P) and compared to a new medium (Pm) with an elemental composition of N 0.0205 S 0.0597 P 0.005 . Cultivation on this medium allowed the increase of EPS concentration up to 2.5 g L −1 , without modification of the EPS productivity (0.096 g L −1 ) and EPS structure. In a second time, photosynthetic activity of the strain was monitored as a function of irradiance and temperature, allowing improvement of kinetic parameters of growth and EPS production. A semi-continuous culture, carried out with the Pm medium, an optimal irradiance and temperature of respectively 360 μmol photons m −2 s −1 and 28 °C led to an EPS process productivity of 0.031 g h −1 instead of 0.020 g h −1 in batch culture. [ABSTRACT FROM AUTHOR]

The asafoetida gum was extracted and purified from oleo-gum-resin of Ferula assa foetida root and characterized by high pressure anions exchange chromatography after acidic hydrolysis. It was composed of Gal:Ara:Rha:GlcA with the ratio 11.5:5.0:2.1:1.0. This monosaccharide composition was found similar to that of a commercial Arabic gum which exhibited a Gal:Ara:Rha:GlcA ratio of 11.7:5.4:3.2:1.0. As the Arabic gum is currently used for its emulsifying properties, the two gums were evaluated for their functional and rheological behaviors. Surface and interfacial tensions values were lower for asafoetida gum compared to Arabic gum. Critical micelle concentration was achieved at concentrations of 0.5% w/w and 1% w/w for asafoetida and Arabic gums, respectively. Values of emulsion capacity, emulsion stability and foaming properties were considerably higher for asafoetida gum in contrast to emulsion activity index that was lower than that of Arabic gum. As those of Arabic gum, solutions of asafoetida gum (2–30% w/w) exhibited Newtonian flow behavior at shear rates between 1 and 500 s −1 . Apparent viscosities of Arabic and asafoetida gums were close and logically decreased by increasing temperature (10–80 °C). Higher viscosities were achieved at higher pH and CaCl 2 concentrations. [ABSTRACT FROM AUTHOR]

Sodium alginate from Nizimuddinia zanardini (an Iranian brown algae) was extracted with acid and alkaline solutions, partially and totally hydrolyzed and analyzed for its biochemical composition. 1 H NMR spectroscopy, SEC-MALLS, HPAEC and FT-IR were performed to determine its structure and its physico-chemical properties. This alginate has a M/G ratio of 1.1, a molecular weight of 103 kDa, a polydispersity index of 1.22, and an intrinsic viscosity of 342 mL/g. Its antioxidant activity was tested by DPPH radical scavenging showing its potential for food preservation. Rheological properties of solutions of this alginate with concentrations between 1 and 5% (w/v) in water and 0.5 M NaCl were investigated indicating a Newtonian fluid type behaviour in water and a shear thinning fluid type behaviour in NaCl solutions. [ABSTRACT FROM AUTHOR]

Plantago notata (Plantaginaceae) is a spontaneous plant from Septentrional Algerian Sahara currently used by traditional healers to treat stomach disorders, inflammations or wound healing. A water-soluble polysaccharide, called PSPN (PolySaccharide fraction from Plantago Notata ), was extracted and purified from the seeds of this semi-arid plant. The structural features of this mucilage were evaluated by colorimetric assays, Fourier transformed infrared spectroscopy (FT-IR), gas chromatography coupled to mass spectrometry (GC/MS) and 1 H/ 13 C Nuclear Magnetic Resonance (NMR) spectroscopy. PSPN is a heteroxylan with a backbone composed of β -(1,3)- d -Xyl p and β -(1,4)- d -Xyl p highly branched, through ( O )-2 and ( O )-3 positions of β -(1,4)- d -Xyl p by various side chains and terminal monosaccharides such as α- l -Ara f -(1,3)- β -d-Xyl p , β - d -Xyl p -(1,2)- β - d -Xyl p , terminal Xyl p or terminal Ara f . The physico-chemical and rheological analysis of this polysaccharide in dilute and semi diluted regimes showed that PSPN exhibites a molecular weight of 2.3 × 10 6 g/mol and a pseudoplastic behavior. [ABSTRACT FROM AUTHOR]