title: Rheological and structural characterization of agar/whey proteins insoluble complexes.
abstract: Complex coacervation between whey proteins and carboxylated or highly sulphated polysaccharides has been widely studied. The aim of this work was to characterise a slightly sulphated polysaccharide (agar) and whey protein insoluble complexes in terms of yield, composition and physicochemical properties as well as to study their rheological behaviour for better understanding their structure. Unlike other sulphated polysaccharides, complexation of agar and whey protein at pH 3 in the absence of a buffering agent resulted in a coacervate that was a gel at 20°C with rheological properties and structure similar to those of simple agar gels, reinforced by proteins electrostatically aggregated to the agar network. The behaviour towards heat treatment was similar to that of agar alone, with a high thermal hysteresis and almost full reversibility. In the presence of citrate buffer, the result was a "flocculated solid", with low water content (75-81%), whose properties were governed by protein behaviour.
authors.affiliation: REQUIMTE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: cmrocha@fe.up.pt.
authors.forename: Cristina M R
authors.initials: CM
authors.lastname: Rocha
authors.affiliation: REQUIMTE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Hiléia K S
authors.initials: HK
authors.lastname: Souza
authors.affiliation: REQUIMTE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; Instituto de Macromoléculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Centro de Tecnologia, Bloco J, 21945-970 Rio de Janeiro, RJ, Brazil.
authors.forename: Natália F
authors.initials: NF
authors.lastname: Magalhães
authors.affiliation: Instituto de Macromoléculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Centro de Tecnologia, Bloco J, 21945-970 Rio de Janeiro, RJ, Brazil.
authors.forename: Cristina T
authors.initials: CT
authors.lastname: Andrade
authors.affiliation: REQUIMTE, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Gonçalves
mesh_terms: D000362:Agar / Q000737:chemistry*; D005427:Flocculation; D005782:Gels / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry*; D012212:Rheology; D012995:Solubility; D014867:Water / Q000737:chemistry; D000067816:Whey Proteins
chemical_list: D005782:Gels; D008894:Milk Proteins; D000067816:Whey Proteins; D014867:Water; D000362:Agar
keywords: Agar; Coacervation; Insoluble complexes; Rheology; Whey proteins