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Title: The phase behaviour, flow behaviour, and interfacial properties of protein-polysaccharide aqueous two-phase systems with sugar
Author: Pörtsch, Asja
ISNI:       0000 0004 2719 8459
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2012
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The aim of this work is to better understand the structuring processes in low fat dairy emulsions. Model sodium caseinate-galactomannan aqueous two-phase systems (NaCAS-GM ATPS) differing in GM-type (locust bean gum (LBG), tara gum (TG), guar gum (GG), fenugreek gum (FG)) and added sugar (trehalose, sucrose, glucose and fructose) were studied by the phase-volume ratio method, rheooptics, and droplet retraction method on phase equilibria, flow behaviour and interfacial properties, respectively, at pH 5.8 and 20°C. The results revealed that the presence of sugar in concentrations 5-40 wt% resulted in an increase in cosolubility of the phases and a decrease in interfacial tension (σ). Sugar concentrations > 40 wt% decreased cosolubility. Based on the mannose:galactose ratio of GM and type of sugar (added in concentration 15 wt%) the best cosolubility and corresponding smallest σ was attributed to FG and trehalose, respectively. The flow of ATPS depended on quiescent microstructure, the shear and physical properties of the phases. In polysaccharide-continuous ATPS, the occurrence of a shear-induced phase inversion event was observed for 0- 20 wt% sugar. A further increase in sugar concentration >20 wt% was found to suppress this phenomenon due decreased viscosity ratio and formation of thread like structures in flow.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TP Chemical technology