Properties of mixed protein/surfactant adsorption layers

Krägel, J.; Wüstneck, R.; Husband, Fiona A.; Wilde, Peter J.; Makievski, A. V.; Grigoriev, D. O.; Li, J.B

doi:10.1016/s0927-7765(98)00094-0

Cited by 85 publications

(88 citation statements)

References 15 publications

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“…6 Globular proteins such as b-lactoglobulin form interconnected elastic networks at interfaces, 39,40 which possess signicantly larger interfacial rheological parameters when compared to surfactants (Table 1). The protein b-casein by contrast is a rather unique case; although strongly surface-active it forms weakly elastic interfaces 41 (Table 1) due to its lack of secondary structure, and consequently forms interfaces, which exhibit surfactant-like behaviour.…”

Section: Resultsmentioning

confidence: 99%

Probing the role of interfacial rheology in the relaxation behaviour between deformable oil droplets using force spectroscopy

et al. 2013

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AFM images of oil droplets obtained by force mapping reveal both their shape and relative elasticity. A more subtle factor which controls stability of the dispersed phase in emulsions is the role of interfacial composition in determining thin fi lm drainage rates. The paper demonstrates how this can be established by pressing lever-bound oil droplets against sessile oil droplets under water. As featured in:See A. Patrick Gunning et al., Soft Matter, 2013, 9, 11473. Probing the role of interfacial rheology in the relaxation behaviour between deformable oil droplets using force spectroscopy A. Patrick Gunning, * Andrew R. Kirby, Peter J. Wilde, Robert Penfold, Nicola C. Woodward and Victor J. Morris An experimental method is presented for investigating the effect of the nature of the interface on the relaxation behaviour accompanying hydrodynamic drainage occurring between oil droplets driven together in aqueous solution. This method is based upon force spectroscopy of droplet-droplet interactions. An atomic force microscope is used to drive two droplets together to a pre-defined force and then monitor relaxation of the force between the droplets. It is suggested that the observed relaxation is controlled by the hydrodynamic drainage of the interlamellar fluid separating the droplets.Data is presented for both ionic (sodium dodecyl sulphate) and non-ionic surfactants (Tween-20), uncoated oil droplets and droplets coated with the proteins, b-casein and b-lactoglobulin. Uncoated droplets, droplets coated with surfactants and droplets coated with the protein b-casein all exhibited fast relaxation, whereas droplets coated with b-lactoglobulin exhibited markedly slower relaxation and more complex behaviour.

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Section: Resultsmentioning

confidence: 99%

Probing the role of interfacial rheology in the relaxation behaviour between deformable oil droplets using force spectroscopy

et al. 2013

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“…The addition of surfactants can modify the microstructure, equilibrium and dynamic adsorption values, and the rheological characteristics of interfacial layers 3,10,11,55 and the interfacial properties of the mixed protein/surfactant system are also quite different from the bulk. Studies of the microstructure at the interface using Brewster Angle Microscopy or Fluorescence Microscopy [56][57][58] or by evaluating local dynamics using micro-rheology reveal the presence of considerable interfacial phase separation with localized surfactant-rich and protein-rich regions 3,4,36 .…”

Section: Protein-surfactant Mixturesmentioning

confidence: 99%

“…The surface topography and the location and distribution of the hydrophobic and hydrophilic moieties determine the amphiphilic character of a protein and consequently its surface activity 6,11 . Due to conformational constraints and improper packing, optimal orientation of these hydrophobic and hydrophilic groups at the interface is sometimes prevented and proteins do not reduce the interfacial tension as dramatically as low molecular weight surfactants which can align and organize themselves at the interface more rapidly and optimally 6,10,11 . However the presence of proteins imparts a substantially higher interfacial elasticity and viscosity than the corresponding low molecular weight surfactants.…”

Section: Protein-surfactant Mixturesmentioning

confidence: 99%

“…Multicomponent mixtures of proteins and surfactants are used in many of these applications, and are also commonly found in many biological systems [6][7][8] including blood: a mixture of serum albumins along with various other surface-active components 6,8 . The addition of surfactants to protein solutions can substantially modify the physiochemical properties of the resulting interface 2,6,[9][10][11] . For example, the interfacial shear viscos- ity (which characterizes resistance to changes in shape at constant area on a two-dimensional interface), is affected by the structure, composition and conformation of the interfacial components of these mixed systems 3,6,9,10,12 .…”

Section: Introductionmentioning

confidence: 99%

“…The addition of surfactants to protein solutions can substantially modify the physiochemical properties of the resulting interface 2,6,[9][10][11] . For example, the interfacial shear viscos- ity (which characterizes resistance to changes in shape at constant area on a two-dimensional interface), is affected by the structure, composition and conformation of the interfacial components of these mixed systems 3,6,9,10,12 . In this study, we focus on the interfacial and bulk rheology of a proteinsurfactant mixture, using solutions of a model globular protein, Bovine Serum Albumin (BSA), mixed with a non-ionic surfactant polysorbate 80 (or Tween 80 TM ).…”

Section: Introductionmentioning

confidence: 99%

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Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

2011

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Protein-surfactant mixtures arise in many industrial and biological systems, and indeed, blood itself is a mixture of serum albumins along with various other surface-active components. Bovine serum albumin (BSA) solutions, and globular proteins in general, exhibit an apparent yield stress in bulk rheological measurements at surprisingly low concentrations. By contrasting interfacial rheological measurements with corresponding interface-free data obtained using a microfluidic rheometer, we show that the apparent yield stress exhibited by these solutions arises from the presence of a viscoelastic layer formed due to the adsorption of protein molecules at the air-water interface. The coupling between instrument inertia and surface elasticity in a controlled stress device also results in a distinctive damped oscillatory strain response during creep experiments known as"creep ringing". We show that this response can be exploited to extract the interfacial storage and loss moduli of the protein interface. The interfacial creep response at small strains can be described by a simple second order system, such as the linear Jeffreys model, however the interfacial response rapidly becomes nonlinear beyond strains of order 1%. We use the two complementary techniques of interfacial rheometry and microfluidic rheometry to examine the systematic changes in the surface and bulk material functions for mixtures of a common non-ionic surfactant, Polysorbate 80, and BSA. It is observed that the nonlinear viscoelastic properties of the interface are significantly suppressed by the presence of even a relatively small amount of surfactant (c surf > 10 −3 wt.%).

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Interfacial Phenomena in Structured Foods

Golding

2012

Food Materials Science and Engineering

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Properties of mixed protein/surfactant adsorption layers

Cited by 85 publications

References 15 publications

Probing the role of interfacial rheology in the relaxation behaviour between deformable oil droplets using force spectroscopy

Probing the role of interfacial rheology in the relaxation behaviour between deformable oil droplets using force spectroscopy

Interfacial viscoelasticity, yielding and creep ringing of globular protein–surfactant mixtures

Interfacial Phenomena in Structured Foods

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