title: Characterization and rheological study of the galactomannan extracted from seeds of Cassia grandis.
abstract: 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.
authors.affiliation: Departamento de Bioquímica/Laboratório de Imunopatologia Keizo Asami-LIKA, Universidade Federal de Pernambuco, Avenue Prof. Moraes Rego s/n, Recife CEP: 50.670-420, PE, Brazil.
authors.forename: Priscilla B S
authors.initials: PB
authors.lastname: Albuquerque
authors.affiliation: Departamento de Física, Universidade Federal de Pernambuco, Avenue prof. Luiz Freire s/n, Recife CEP 50670-901, PE, Brazil.
authors.forename: Wilson
authors.initials: W
authors.lastname: Barros
authors.affiliation: Laboratório 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, Brazil.
authors.forename: Gustavo R C
authors.initials: GR
authors.lastname: Santos
authors.affiliation: Departamento de Bioquímica/Laboratório de Imunopatologia Keizo Asami-LIKA, Universidade Federal de Pernambuco, Avenue Prof. Moraes Rego s/n, Recife CEP: 50.670-420, PE, Brazil.
authors.forename: Maria T S
authors.initials: MT
authors.lastname: Correia
authors.affiliation: Laboratório 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, Brazil.
authors.forename: Paulo A S
authors.initials: PA
authors.lastname: Mourão
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, Braga 4710-057, Portugal.
authors.forename: José A
authors.initials: JA
authors.lastname: Teixeira
authors.affiliation: Departamento de Bioquímica/Laboratório de Imunopatologia Keizo Asami-LIKA, Universidade Federal de Pernambuco, Avenue Prof. Moraes Rego s/n, Recife CEP: 50.670-420, PE, Brazil. Electronic address: mgcc@ufpe.br.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Carneiro-da-Cunha
mesh_terms: D002366:Cassia / Q000033:anatomy & histology / Q000737:chemistry*; D004548:Elasticity; D005690:Galactose / Q000031:analogs & derivatives; D008351:Mannans / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D012212:Rheology; D012639:Seeds / Q000737:chemistry*; D014783:Viscosity
chemical_list: D008351:Mannans; D010936:Plant Extracts; C012990:galactomannan; D005690:Galactose
keywords: Cassia grandis; Characterization.; Galactomannan; NMR; Rheology; X-ray