Étude de l'interaction associative entre la β-lactoglobuline et le xanthane natif ou le xanthane traité aux hautes pressions hydrodynamiques

Authors: Laneuville Ballester, Sandra Isabel
Advisor: Turgeon, SylviePaquin, Paul
Other Title(s): Étude de l'interaction associative entre la bêta-lactoglobuline et le xanthane natif ou le xanthane traité aux hautes pressions hydrodynamiques
Abstract: The associative interaction between β-lactoglobulin and xanthan gum (native or treated by high hydrodynamic pressures) resulting in the formation of electrostatic complexes was studied by several chemical and physical techniques. The main objective was to develop a fundamental knowledge of this system at a molecular level, to better understand the interactions between proteins and anionic polysaccharides. The associative phase separation in this system proceeded via a nucleation and growth mechanism that resulted in the formation of distinct fractal structures. Namely, differences in size, internal structure (compactness), and solubility were obtained depending principally on the pH and initial protein to polysaccharide ratio; which, in turn governed molecular charge density and mass action equilibrium effects determining the structuration processes. The important effects of the acidification method and the shearing forces applied during complexation were also identified. Particularly, it was revealed that when shear forces were applied during complexation the size and the structure of interpolymeric complexes were determined by restructuring processes set by a competition between attractive electrostatic forces and rupture forces caused by flow. Moreover, it was found that the aggregation pattern of xanthan gum was responsible for the formation of the different structures since it is the polysaccharide that acts as the support during complexation. Accordingly, at slow rates of acidification, a modification of the molecular weight of xanthan gum can control the size of the complexes. Therefore, the characteristics and functional properties of the complexes can be modified and tailored by adjusting the initial parameters and the conditions present during their manufacture.
Document Type: Thèse de doctorat
Issue Date: 2004
Open Access Date: 11 April 2018
Permalink: http://hdl.handle.net/20.500.11794/18223
Grantor: Université Laval
Collection:Thèses et mémoires

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