title: Rheological studies of the fucose-rich exopolysaccharide FucoPol.
abstract: In this work, the solution properties of the bacterial fucose-rich polysaccharide, FucoPol, were studied. The effect of pH (3.5-10.0) and ionic strength (0.02-1.0 M NaCl) on the intrinsic viscosity and steady shear flow were evaluated using a central composite rotatable design of experiments and surface response methodology. FucoPol's intrinsic and apparent viscosities presented a quite low variation under a wide range of pH (3.5-8.0) and ionic strength (0.05-0.50 M NaCl) values. FucoPol produced viscous solutions with shear-thinning behavior at different polymer concentrations (0.2-1.2 wt.%). Flow curves were successfully described by the Cross model. The viscosity of the first Newtonian plateau varied from 0.01 to 2.47 Pas for polymer concentrations from 0.2 to 1.2 wt.%, and the dependence of the estimated relaxation time with polymer concentration suggests a large degree of interaction between FucoPol molecules. Given the results obtained, FucoPol is proposed as thickening agent for applications in which stability of the apparent viscosity under pH and ionic strength variations is required.
authors.affiliation: UCIBIO-REQUIMTE, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Cristiana A V
authors.initials: CA
authors.lastname: Torres
authors.affiliation: LAQV-REQUIMTE, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Ana R V
authors.initials: AR
authors.lastname: Ferreira
authors.affiliation: UCIBIO-REQUIMTE, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Filomena
authors.initials: F
authors.lastname: Freitas
authors.affiliation: UCIBIO-REQUIMTE, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Maria A M
authors.initials: MA
authors.lastname: Reis
authors.affiliation: LAQV-REQUIMTE, Chemistry Department, FCT/Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Coelhoso
authors.affiliation: LEAF - Linking Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Sousa
authors.affiliation: LEAF - Linking Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017, Portugal. Electronic address: vitoralves@isa.ulisboa.pt.
authors.forename: Vítor D
authors.initials: VD
authors.lastname: Alves
mesh_terms: D004548:Elasticity; D005503:Food Additives / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012212:Rheology; D012996:Solutions; D014783:Viscosity
chemical_list: D005503:Food Additives; D011135:Polysaccharides, Bacterial; D012996:Solutions
keywords: Fucose-rich polysaccharide; Solution properties, Rheology