title: Rheological behavior of high methoxyl pectin from the pulp of tamarillo fruit (Solanum betaceum).
abstract: Rheological behavior of a high methyl-esterified pectic fraction (STW-A) from tamarillo was evaluated at different concentrations in water and with sucrose (50% w/w, pH 3). STW-A dispersions at 3, 5, and 8% (w/w) showed low apparent viscosities, shear-thinning and liquid-like behaviors. They were well fitted using the Ostwald-de Waele model and obey the Cox-Merz rule. The viscosity and the viscoelastic behavior were greatly modified by the presence of sucrose. STW-A at 1% (+ sucrose) showed shear-thinning and concentrated solution behavior. Pronounced shear-thinning and gel-like behaviors were obtained with STW-A at 2 and 3% (+ sucrose). Their flow curves profiles were better fitted using the Hershel-Bulkley model and not followed the Cox and Merz rule. Temperature sweeps (5-80°C) showed that STW-A formed thermostable gels. Altogether, our results suggested tamarillo can be a new source of pectin with potential applications as thickeners/gelling agents depending on solvent or applied processes.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980 Curitiba, PR, Brazil.
authors.forename: Georgia Erdmann
authors.initials: GE
authors.lastname: do Nascimento
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980 Curitiba, PR, Brazil.
authors.forename: Fernanda F
authors.initials: FF
authors.lastname: Simas-Tosin
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980 Curitiba, PR, Brazil.
authors.forename: Marcello
authors.initials: M
authors.lastname: Iacomini
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980 Curitiba, PR, Brazil.
authors.forename: Philip Albert James
authors.initials: PA
authors.lastname: Gorin
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980 Curitiba, PR, Brazil. Electronic address: lucimaramcc@ufpr.br.
authors.forename: Lucimara M C
authors.initials: LM
authors.lastname: Cordeiro
mesh_terms: D004548:Elasticity; D005638:Fruit / Q000737:chemistry; D008962:Models, Theoretical; D010368:Pectins / Q000737:chemistry*; D012212:Rheology; D032322:Solanum; D013395:Sucrose / Q000737:chemistry; D014783:Viscosity
chemical_list: D013395:Sucrose; D010368:Pectins
keywords: Gel; Pectin; Rheology; Solanum betaceum; Tamarillo