Characterization and rheological study of the galactomannan extracted from seeds of Cassia grandis

author Priscilla B.S. Albuquerque, Wilson Barros, Gustavo R.C. Santos, Maria T.S. Correia, Paulo A.S. Mourão, José A. Teixeira, Maria G. Carneiro-da-Cunha
his workplace 1Departamento de Bioquímica/Laboratório de Imunopatologia Keizo Asami-LIKA, Universidade Federal de Pernambuco, Avenue Prof. Moraes Rego s/n, Recife CEP: 50.670-420, PE, Brazil2Departamento de Física, Universidade Federal de Pernambuco, Avenue prof. Luiz Freire s/n, Recife CEP 50670-901, PE, Brazil3Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho and Programa de Glicobiologia, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil4IBB–Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, Braga 4710-057, Portugal
periodicalCarbohydrate Polymers, 2014, Vol.104 , pp.127-134
sourceElsevier Journal
key word Galactomannan; Cassia grandis; Rheology; X-ray; NMR; Characterization.;
Original abstractAbstract(#br)Galactomannan extracted from seeds of Cassia grandis with 0.1M NaCl, followed by ethanol precipitation, presented a yield of 36±8%. The polysaccharide has a constant mannose/galactose ratio (2.44:1). Methylation analysis, one and two dimensional NMR spectroscopy confirmed that the polysaccharide has a central core composed of 4-linked β-mannose units, with branches of galactose, linked to the carbohydrate core through α(1–6) linkage. The amorphous nature of the galactomannan was confirmed by X-ray diffraction. Rheological characterization exhibited Newtonian plateaus followed by shear-thinning zones characteristic of polymer solutions up to 1.5% (w/v) and above this value the system exhibited yield stress associated with a weak gel. Adjusting stress-strain curves confirmed a 1.6% (w/v) as the galactomannan concentration value for the sol–gel transition. These results indicate that the galactomannan extracted from C. grandis seeds presents rheological characteristics suitable for applications in pharmaceutical, biomedical, cosmetic and food industries.
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