title: Milk protein-gum tragacanth mixed gels: effect of heat-treatment sequence.
abstract: The aim of this study was to investigate the role of the heat-treatment sequence of biopolymer mixtures as a formulation parameter on the acid-induced gelation of tri-polymeric systems composed of sodium caseinate (Na-caseinate), whey protein concentrate (WPC), and gum tragacanth (GT). This was studied by applying four sequences of heat treatment: (A) co-heating all three biopolymers; (B) heating the milk-protein dispersion and the GT dispersion separately; (C) heating the dispersion containing Na-caseinate and GT together and heating whey protein alone; and (D) co-heating whey protein with GT and heating Na-caseinate alone. According to small-deformation rheological measurements, the strength of the mixed-gel network decreased in the order: C>B>D>A samples. SEM micrographs show that the network of sample C is much more homogenous, coarse and dense than sample A, while the networks of samples B and D are of intermediate density. The heat-treatment sequence of the biopolymer mixtures as a formulation parameter thus offers an opportunity to control the microstructure and rheological properties of mixed gels.
authors.affiliation: Department of Food Science and Technology, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, 193954741 Tehran, Iran. Electronic address: masoudhatami.018@gmail.com.
authors.forename: Masoud
authors.initials: M
authors.lastname: Hatami
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nejatian
authors.forename: Mohammad Amin
authors.initials: MA
authors.lastname: Mohammadifar
authors.forename: Hanieh
authors.initials: H
authors.lastname: Pourmand
mesh_terms: D005782:Gels; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D055595:Mechanical Phenomena; D008894:Milk Proteins / Q000737:chemistry*; D012212:Rheology; D013997:Time Factors; D014144:Tragacanth / Q000737:chemistry*
chemical_list: D005782:Gels; D008894:Milk Proteins; D014144:Tragacanth
keywords: Biopolymer interaction; Formulation parameters; Gum tragacanth; Heat-treatment sequence; Microstructure; Milk protein; Rheology