β-Lactoglobulin adsorption layers at the water/air surface: 1. Adsorption kinetics and surface pressure isotherm: Effect of pH and ionic strength

Ulaganathan, V.; Retzlaff, I.; Won, Jooyoung; Gochev, Georgi; Gehin-Delval, Cécile; Leser, Martin E.; Noskov, Boris A.; Miller, R.

doi:10.1016/j.colsurfa.2016.03.008

Cited by 42 publications

(51 citation statements)

References 38 publications

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“…Furthermore, we shall apply this approach, firstly, to reconsider our previous results on BLG adsorption layers at pH 7 [28] and, secondly, to analyze in this manner new experimental data obtained for BLG solutions at pH 3 and pH 5. The results are expected to well complement previous findings on the unique effect of pH on the properties of BLG adsorption layers at the water/air interface and on corresponding foam films and foams [24,[40][41][42][43][44][45].…”

Section: Introductionsupporting

confidence: 86%

“…In this line, the intermediate values of c Π=0.1 and c* for pH 5 (negligible net charge) are surprising. Such "anomalous" behavior of BLG at pH 5 and at relatively low protein concentrations (c ≤ 10 −7 M) was observed in previous adsorption kinetics studies [43]. Note that an analogous behavior was reported also for β-casein [27].…”

Section: Precritical Region Of the Blg Adsorption Layersupporting

confidence: 80%

“…Figure 1a,b show noticeable shifts along the c-axis of the Π(c) and Γ(c) isotherms as the values for both characteristic concentrations c Π=0.1 and c* decrease in the order pH 3 < pH 5 < pH 7. Concerning the cases of pH 7 and pH 3, the lower surface activity at pH 3 is attributed to the higher protein net charge [40,43,65,66] within the concept of an electrostatic barrier of adsorption [65][66][67]. Effects of other pHdependent factors, like exposed hydrophobicity, protein rigidity and degree of unfolding upon adsorption have also been considered in the literature [68][69][70].…”

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

“…This means that a certain minimum amount of adsorbed protein molecules is required to generate measurable Π-values. This phenomenon is the background of the so-called induction time in the dynamic surface pressure of protein solutions [43,55,73,74]. The origin of such behaviors is a first-order 2-D "gaseous" to "liquid expanded" phase transition, which occurs at extremely low Π [73,74].…”

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

“…At the very low c near the onset of Π, the induction times in the adsorption kinetics of BLG are very long (hours) [43], and, under these conditions, we consider the adsorbed protein molecules have approached the limit of unfolding upon adsorption [15,16], which apparently is pH-dependent. Note that the area "per" molecule ω is, in fact, slightly larger than the real area "of" a molecule at the interface, due to packing effects.…”

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

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β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

Gochev

Kovalchuk

Aksenenko

et al. 2021

Colloids and Interfaces

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The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

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Section: Introductionsupporting

confidence: 86%

Section: Precritical Region Of the Blg Adsorption Layersupporting

confidence: 80%

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

Section: Precritical Region Of the Blg Adsorption Layermentioning

confidence: 99%

See 3 more Smart Citations

β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

Gochev

Kovalchuk

Aksenenko

et al. 2021

Colloids and Interfaces

View full text Add to dashboard Cite

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Foams

Gochev

Ulaganathan

Miller

2016

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. History of Liquid Foam 3. Fundamentals of Liquid Foam 3.1. Foam Generation 3.1.1. Bubble Detaching from a Capillary 3.1.2. Rising Bubble in Liquid 3.1.3. Collision with Surface 3.2. Foam Structure 3.3. Foam Properties and Stability 3.3.1. Foam Drainage 3.3.2. Gas Diffusion in Foam 3.3.3. Bubble Coalescence 3.4. Foam Rheology 3.5. Foams in Microgravity 4. Foam Stabilizers 4.1 4.1. Surfactants 4.2 4.2. Proteins 4.3. Nanoparticles 5. Antifoamers and Defoamers 6. Applications in Industry 6.1. Liquid Foams 6.1.1. Foams in Separation Processes 6.1.2. Foams in Detergency, Pharmacy, and Cosmetics 6.1.3. Foams in Food 6.1.4. Foams in Firefighting 6.2. Solid Foams 6.2.1. Polymeric Foams 6.2.2. Metallic Foams 6.2.3. Ceramic Foam

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