Abstract
Aqueous two-phase biopolymer-surfactant mixtures have so far received only little attention. Here, the behaviour of such mixtures was investigated adopting methods well established for aqueous two-phase biopolymer-biopolymer mixtures. The pullulan-sodiurn clodecyl sulphate (SDS) mixture, in which phase separation can be induced, and then enhanced by the addition of sodium chloride (NaCl), was chosen as a model system and its morphology and rheology under shear was analysed. Rheological measurements on phase-separated mixtures revealed that the viscosity depends on the chemical composition of the single phases, their viscosity ratio and volume fraction. Optical observations showed droplet-like morphology over a wide range of shear rates at low volume fractions of one phase, and co-continuous structures including string phases at high volume fractions and shear rates. For more concentrated systems, co-continuous structures were observed at all shear rates investigated, whereby in some cases string phases developed at high shear rates. (C) 2007 Elsevier Ltd. All rights reserved.
Original language | English |
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Pages (from-to) | 121-129 |
Number of pages | 9 |
Journal | Food Hydrocolloids |
Volume | 22 |
DOIs | |
Publication status | Published - 1 Jan 2008 |
Keywords
- morphology
- surfactant
- rheology
- co-continuity
- biopolymer
- aqueous two-phase systems