ABSTRACT
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. 1H 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 103â¯kDa, a polydispersity index of 1.22, and an intrinsic viscosity of 342â¯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 0.5â¯M NaCl were investigated indicating a Newtonian fluid type behaviour in water and a shear thinning fluid type behaviour in NaCl solutions.
Subject(s)
Alginates , Free Radical Scavengers/chemistry , Phaeophyceae/chemistry , Seaweed/chemistry , Alginates/chemistry , Alginates/isolation & purification , Glucuronic Acid/chemistry , Glucuronic Acid/isolation & purification , Hexuronic Acids/chemistry , Hexuronic Acids/isolation & purification , IranABSTRACT
Microparticles of curdlan, synthesized through crosslinking with epichlorohydrin in organic suspension media, were chemically modified with the aim of introducing strongly and/or weakly acidic anionic and palmitoyl hydrophobic groups. Microparticles of both curdlan and curdlan derivatives were physico-chemically characterized. Study of the interaction with enzymes, such as lysozyme, and vaccines, such as tetanus anatoxin, showed a co-operative protein retention effect, induced by electrostatic and hydrophobic forces. The results of the in vitro release studies on support-protein complexes recommend them as potential controlled release systems.
Subject(s)
Microspheres , Muramidase/metabolism , Proteins/metabolism , Vaccines/metabolism , beta-Glucans/chemistry , beta-Glucans/chemical synthesis , Carbohydrate Conformation , Carbohydrate Sequence , Enzymes, Immobilized/metabolism , Ion Exchange , Isotonic Solutions , Kinetics , Microscopy, Electron, Scanning , Molecular Sequence Data , Temperature , Tetanus Toxin/metabolism , Time Factors , beta-Glucans/metabolismABSTRACT
The present article focuses on the comparative study of physicochemical properties of two ionic pullulan derivatives modified by 10 or 35 C8 chains per 100 anhydroglucose units, named CMP10C8 and CMP35C8, respectively. In aqueous solutions, these derivatives exhibited an associative behavior as evidenced by pyrene fluorescence spectroscopy. This phenomenon, which stems from intra- and/or intermolecular interactions between the hydrophobic groups grafted on the polymer backbone, results in the formation of more or less condensed aggregates depending on the C8 ratio and the ionic strength of the media. The hydrophobically modified pullulans also displayed surface properties. Their adsorption at the air-solution interface was assessed from surface tension measurements. The results showed that both hydrophobized polymers adsorb in a coil conformation occupying a large interfacial molecular area. The comparison of these molecular areas indicated that CMP35C8 adopts a more shrunken conformation at the interface than CMP10C8, due to stronger intramolecular interactions. The stability of the adsorbed monolayer under bulk dilution was investigated by ellipsometric measurements. Whereas bulk dilution had no effect on the stability of the adsorbed CMP35C8 film, it provoked significant changes in the adsorbed CMP10C8 monolayer. The stability of the CMP35C8 monolayers was attributed to the existence of intermolecular associations between the adsorbed coils.
