1
|
Trojánek A, Mareček V, Samec Z. Bovine serum albumin adsorption at a polarized water/1,2‐dichloroethane interface with no effect on the ion transfer kinetics. ChemElectroChem 2022. [DOI: 10.1002/celc.202200409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Antonín Trojánek
- J Heyrovsky Institute of Physical Chemistry Czech Academy of Sciences: Ustav fyzikalni chemie J Heyrovskeho Akademie Ved Ceske Republiky Department of biophysics Dolejškova 3 18223 Prague 8 CZECH REPUBLIC
| | - Vladimír Mareček
- J Heyrovsky Institute of Physical Chemistry Czech Academy of Sciences: Ustav fyzikalni chemie J Heyrovskeho Akademie Ved Ceske Republiky Management Dolejskova 3 18223 Prague 8 CZECH REPUBLIC
| | - Zdenek Samec
- J Heyrovsky Institute of Physical Chemistry Czech Academy of Sciences: Ustav fyzikalni chemie J Heyrovskeho Akademie Ved Ceske Republiky Department of Electrocatalysis Dolejskova 3 18223 Prague 8 CZECH REPUBLIC
| |
Collapse
|
2
|
The Importance of Interfacial Tension in Emulsification: Connecting Scaling Relations Used in Large Scale Preparation with Microfluidic Measurement Methods. CHEMENGINEERING 2020. [DOI: 10.3390/chemengineering4040063] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This paper starts with short descriptions of emulsion preparation methods used at large and smaller scales. We give scaling relations as they are generally used, and focus on the central role that interfacial tension plays in these relations. The actual values of the interfacial tension are far from certain given the dynamic behavior of surface-active components, and the lack of measurement methods that can be applied to conditions as they occur during large-scale preparation. Microfluidic techniques are expected to be very instrumental in closing this gap. Reduction of interfacial tension resulting from emulsifier adsorption at the oil-water interface is a complex process that consists of various steps. We discuss them here, and present methods used to probe them. Specifically, methods based on microfluidic tools are of great interest to study short droplet formation times, and also coalescence behavior of droplets. We present the newest insights in this field, which are expected to bring interfacial tension observations to a level that is of direct relevance for the large-scale preparation of emulsions, and that of other multi-phase products.
Collapse
|
3
|
A Multi-Scale Approach to Modeling the Interfacial Reaction Kinetics of Lipases with Emphasis on Enzyme Adsorption at Water-Oil Interfaces. Processes (Basel) 2020. [DOI: 10.3390/pr8091082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The enzymatic hydrolysis of triglycerides with lipases (EC 3.1.1.3.) involves substrates from both water and oil phases, with the enzyme molecules adsorbed at the water-oil (w/o) interface. The reaction rate depends on lipase concentration at the interface and the available interfacial area in the emulsion. In emulsions with large drops, the reaction rate is limited by the surface area. This effect must be taken into account while modelling the reaction. However, determination of the interfacial saturation is not a trivial matter, as enzyme molecules have the tendency to unfold on the interface, and form multi-layer, rendering many enzyme molecules unavailable for the reaction. A multi-scale approach is needed to determine the saturation concentration with specific interfacial area so that it can be extrapolated to droplet swarms. This work explicitly highlights the correlation between interfacial adsorption and reaction kinetics, by integration of the adsorption kinetics into the enzymatic reaction. The rate constants were fitted globally against data from both single droplet and drop swarm experiments. The amount of adsorbed enzymes on the interface was measured in a single drop with a certain surface area, and the enzyme interfacial loading was estimated by Langmuir adsorption isotherm.
Collapse
|
4
|
Zaccagnino F, Audebert A, Cox SJ. Simulation of surfactant transport during the rheological relaxation of two-dimensional dry foams. Phys Rev E 2018; 98:022801. [PMID: 30253619 DOI: 10.1103/physreve.98.022801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Indexed: 11/07/2022]
Abstract
We describe a numerical model to predict the rheology of two-dimensional dry foams. The model accurately describes soap film curvature and viscous friction with the walls, and includes the transport of surfactant within the films and across the vertices where films meet. It accommodates the changes in foam topology that occur when a foam flows and, in particular, accurately represents the relaxation of the foam following a topological change. The model is validated against experimental data, allowing the prediction of elastic and viscous parameters associated with different surfactant solutions.
Collapse
Affiliation(s)
- F Zaccagnino
- Department of Mathematics, Aberystwyth University, Aberystwyth, Ceredigion, SY23 3BZ, United Kingdom
| | - A Audebert
- STLO, UMR1253, INRA, Agrocampus Ouest, 35000 Rennes, France
| | - S J Cox
- Department of Mathematics, Aberystwyth University, Aberystwyth, Ceredigion, SY23 3BZ, United Kingdom
| |
Collapse
|
5
|
Berton-Carabin CC, Sagis L, Schroën K. Formation, Structure, and Functionality of Interfacial Layers in Food Emulsions. Annu Rev Food Sci Technol 2018; 9:551-587. [DOI: 10.1146/annurev-food-030117-012405] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Leonard Sagis
- Physics and Physical Chemistry of Foods, Wageningen University, 6708 WG Wageningen, The Netherlands
| | - Karin Schroën
- Food Process Engineering Group, Wageningen University, 6708 WG Wageningen, The Netherlands
| |
Collapse
|
6
|
Capture of LPS traces in aqueous solutions by tectomers of four-antennary oligoglycines. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.02.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
7
|
Garakani TM, Richter MJ, Böker A. Controlling the bio-inspired synthesis of silica. J Colloid Interface Sci 2017; 488:322-334. [PMID: 27838557 DOI: 10.1016/j.jcis.2016.10.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 11/24/2022]
Abstract
The influence of different parameters on the silicification procedure using lysozyme is reported. When polyethoxysiloxane (PEOS), an internally crosslinked silica reservoir, is used, regular structures with a narrow size distribution could be obtained only via introducing the silica precursor in two steps including initial dropping and subsequent addition of residual oil phase in one portion. We found that mixing sequence of mineralizing agents in the presence of a positively charged surfactant plays a key role in terms of silica precipitation when tetraethoxyorthosilicate (TEOS) is the oil phase. In contrast, well-mineralized crumpled features with high specific surface area could be synthesized in the presence of PEOS as a silica precursor polymer, regardless of mixing sequence. Moreover, introducing sodium dodecyl sulfate (SDS) as a negatively charged surfactant resulted in regular silica sphere formation only in combination with hexylene glycol (MPD) as a specific co-solvent. Finally, it is demonstrated that by inclusion of different nanoparticles even more sophisticated hybrid materials can be generated.
Collapse
Affiliation(s)
- Tayebeh Mirzaei Garakani
- DWI - Leibniz-Institut für Interaktive Materialien e.V., Lehrstuhl für Makromolekulare Materialien und Oberflächen, RWTH Aachen University, Forckenbeckstr. 50, D-52062 Aachen, Germany
| | - Marina Juliane Richter
- DWI - Leibniz-Institut für Interaktive Materialien e.V., Lehrstuhl für Makromolekulare Materialien und Oberflächen, RWTH Aachen University, Forckenbeckstr. 50, D-52062 Aachen, Germany
| | - Alexander Böker
- Fraunhofer Institute for Applied Polymer Research (IAP), Geiselbergstr. 69, 14476 Potsdam-Golm, Germany; Lehrstuhl für Polymermaterialien und Polymertechnologie, Universität Potsdam, 14476 Potsdam-Golm, Germany.
| |
Collapse
|
8
|
|
9
|
Richter MJ, Schulz A, Subkowski T, Böker A. Adsorption and rheological behavior of an amphiphilic protein at oil/water interfaces. J Colloid Interface Sci 2016; 479:199-206. [DOI: 10.1016/j.jcis.2016.06.062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/24/2016] [Accepted: 06/27/2016] [Indexed: 10/21/2022]
|
10
|
Kezwoń A, Góral I, Frączyk T, Wojciechowski K. Effect of surfactants on surface activity and rheological properties of type I collagen at air/water interface. Colloids Surf B Biointerfaces 2016; 148:238-248. [PMID: 27616064 DOI: 10.1016/j.colsurfb.2016.08.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/25/2016] [Accepted: 08/30/2016] [Indexed: 01/22/2023]
Abstract
We describe the effect of three synthetic surfactants (anionic - sodium dodecyl sulfate (SDS), cationic - cetyltrimethylammonium bromide (CTAB) and nonionic - Triton X-100 (TX-100)) on surface properties of the type I calf skin collagen at the air/water interface in acidic solutions (pH 1.8). The protein concentration was fixed at 5×10-6molL-1 and the surfactant concentration was varied in the range 5×10-6molL-1-1×10-4molL-1, producing the protein/surfactant mixtures with molar ratios of 1:1, 1:2, 1:5, 1:10 and 1:20. An Axisymmetric Drop Shape Analysis (ADSA) method was used to determine the dynamic surface tension and surface dilatational moduli of the mixed adsorption layers. Two spectroscopic techniques: UV-vis spectroscopy and fluorimetry allowed us to determine the effect of the surfactants on the protein structure. The thermodynamic characteristic of the mixtures was studied using isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). Modification of the collagen structure by SDS at low surfactant/protein ratios has a positive effect on the mixture's surface activity with only minor deterioration of the rheological properties of the adsorbed layers. The collagen/CTAB mixtures do not show that pronounced improvement in surface activity, while rheological properties are significantly deteriorated. The mixtures with non-ionic TX-100 do not show any synergistic effects in surface activity.
Collapse
Affiliation(s)
- Aleksandra Kezwoń
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Ilona Góral
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland
| | - Tomasz Frączyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Kamil Wojciechowski
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664, Warsaw, Poland.
| |
Collapse
|
11
|
He Y, Yazhgur P, Salonen A, Langevin D. Adsorption-desorption kinetics of surfactants at liquid surfaces. Adv Colloid Interface Sci 2015; 222:377-84. [PMID: 25307125 DOI: 10.1016/j.cis.2014.09.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
Abstract
The paper discusses adsorption and desorption energy barriers for macroscopic interfaces of surfactant solutions. Literature data suggest that adsorption and desorption are not always fully diffusion controlled. Apart from electrostatic barriers that lead to strong deviations, other types of barriers are less easy to identify, because smaller deviations from diffusion controlled mechanisms are evidenced. Complete models involving both diffusion and sorption barriers are very complex and involve many adjustable parameters, making the data analysis frequently unreliable. Empirical equations of state are used in most cases, although they are inaccurate, especially close to the cmc. The variation of sorption energies with surface concentration is not accurately described in the models. Finally, convection can mask the effect of sorption energy barriers. Experiments are presented to illustrate the main difficulties encountered.
Collapse
|
12
|
Fainerman VB. In honour of the 65th birthday of Reinhard Miller. Adv Colloid Interface Sci 2015; 222:1-8. [PMID: 26111457 DOI: 10.1016/j.cis.2015.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
13
|
Ettelaie R, Dickinson E, Pugnaloni L. First-order phase transition during displacement of amphiphilic biomacromolecules from interfaces by surfactant molecules. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:464109. [PMID: 25347051 DOI: 10.1088/0953-8984/26/46/464109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The adsorption of surfactants onto a hydrophobic interface, already laden with a fixed number of amphiphilic macromolecules, is studied using the self consistent field calculation method of Scheutjens and Fleer. For biopolymers having unfavourable interactions with the surfactant molecules, the adsorption isotherms show an abrupt jump at a certain value of surfactant bulk concentration. Alternatively, the same behaviour is exhibited when the number of amphiphilic chains on the interface is decreased. We show that this sudden jump is associated with a first-order phase transition, by calculating the free energy values for the stable and the metastable states at both sides of the transition point. We also observe that the transition can occur for two approaching surfaces, from a high surfactant coverage phase to a low surfactant coverage one, at sufficiently close separation distances. The consequence of this finding for the steric colloidal interactions, induced by the overlap of two biopolymer + surfactant films, is explored. In particular, a significantly different interaction, in terms of its magnitude and range, is predicted for these two phases. We also consider the relevance of the current study to problems involving the competitive displacement of proteins by surfactants in food colloid systems.
Collapse
Affiliation(s)
- Rammile Ettelaie
- Food Colloids Group, School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | | | | |
Collapse
|
14
|
Stanimirova RD, Marinova KG, Danov KD, Kralchevsky PA, Basheva ES, Stoyanov SD, Pelan EG. Competitive adsorption of the protein hydrophobin and an ionic surfactant: Parallel vs sequential adsorption and dilatational rheology. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
15
|
Chen W, Inoue Y, Ishihara K. Quantitative evaluation of interaction force of fibrinogen at well-defined surfaces with various structures. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2014; 25:1629-40. [DOI: 10.1080/09205063.2014.936925] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
16
|
Polyelectrolyte-surfactant complexes and their influence on the wettability of different polymer surfaces. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3241-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
17
|
Vitasari D, Grassia P, Martin P. Simulation of dynamics of adsorption of mixed protein–surfactant on a bubble surface. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2012.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
|
19
|
|
20
|
van Kempen SEJ, Maas K, Schols HA, van der Linden E, Sagis LM. Interfacial properties of air/water interfaces stabilized by oligofructose palmitic acid esters in the presence of whey protein isolate. Food Hydrocoll 2013. [DOI: 10.1016/j.foodhyd.2012.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
21
|
Dan A, Wüstneck R, Krägel J, Aksenenko EV, Fainerman VB, Miller R. Adsorption and dilational rheology of mixed β-casein/DoTAB layers formed by sequential and simultaneous adsorption at the water/hexane interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:2233-2241. [PMID: 23347396 DOI: 10.1021/la304664x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The interfacial behavior of β-casein (βCS) has been investigated in presence of the cationic surfactant dodecyl trimethyl ammonium bromide (DoTAB) at the water/hexane interface and compared to that obtained for the water/air interface. The used experimental technique is a drop profile analysis tensiometer specially equipped with a coaxial double capillary, which allows investigation of sequential adsorption of individual components besides the traditional simultaneous adsorption of two species. This method also provides the dilational rheological measurements based on low frequency harmonic drop oscillations. The tensiometric results show that the equilibrium states of the mixed βCS/DoTAB layers built up on the two different routes do not differ significantly, that is, the general compositions of the mixed layers are similar. However, the results of dilational rheology for the two adsorption strategies are remarkably different indicating different dynamic characteristics of the adsorbed layers. These findings suggest that the respective mixed layers are more proteinlike if they are formed via sequential adsorption and more surfactant-like after simultaneous adsorption. In contrast to the W/A interface, at the W/H interface proteins remain at the interface once adsorbed and cannot be displaced just by competitive adsorption of surfactants.
Collapse
Affiliation(s)
- Abhijit Dan
- Max-Planck Institute of Colloids & Interfaces, Potsdam/Golm, Germany.
| | | | | | | | | | | |
Collapse
|
22
|
Maestro A, Kotsmar C, Javadi A, Miller R, Ortega F, Rubio RG. Adsorption of β-Casein–Surfactant Mixed Layers at the Air–Water Interface Evaluated by Interfacial Rheology. J Phys Chem B 2012; 116:4898-907. [DOI: 10.1021/jp301031y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Armando Maestro
- Departamento de Química
Física I, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain
| | - Csaba Kotsmar
- Department of Chemical and Biomolecular
Engineering, University of California at Berkeley, Berkeley, California, United States
- Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm, Germany
| | - Aliyar Javadi
- Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm, Germany
| | - Reinhard Miller
- Max-Planck Institute of Colloids and Interfaces, Potsdam-Golm, Germany
| | - Francisco Ortega
- Departamento de Química
Física I, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain
| | - Ramón G. Rubio
- Departamento de Química
Física I, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain
| |
Collapse
|
23
|
Foam films from mixed solutions of bovine serum albumin and n-dodecyl-β-d-maltoside. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
24
|
|
25
|
Szyk-Warszyńska L, Piekoszewska J, Warszyński P. Formation and stability of poly-L-lysine/casein multilayers. ADSORPTION 2010. [DOI: 10.1007/s10450-010-9227-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
26
|
Sankaranarayanan K, Dhathathreyan A, Miller R. Assembling Fibrinogen at Air/Water and Solid/Liquid Interfaces Using Langmuir and Langmuir−Blodgett Films. J Phys Chem B 2010; 114:8067-75. [DOI: 10.1021/jp100896b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | | | - Reinhard Miller
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, FRG
| |
Collapse
|
27
|
Equilibrium and dynamics of adsorption of mixed β-casein/surfactant solutions at the water/hexane interface. Colloids Surf A Physicochem Eng Asp 2010. [DOI: 10.1016/j.colsurfa.2009.04.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
28
|
Lucero Caro A, Rodríguez Niño MR, Rodríguez Patino JM. Topography of dipalmitoyl-phosphatidyl-choline monolayers penetrated by β-casein. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
29
|
Szyk-Warszyńska L, Gergely C, Jarek E, Cuisinier F, Socha RP, Warszyński P. Calcium uptake by casein embedded in polyelectrolyte multilayer. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.01.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
30
|
Caro AL, Rodríguez Niño MR, Rodríguez Patino JM. Dynamics of penetration of dipalmitoyl-phosphatidyl-choline (DPPC) monolayers by β-casein. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.03.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
31
|
Ruíz-Henestrosa VP, Sánchez CC, Pedroche JJ, Millán F, Rodríguez Patino JM. Improving the functional properties of soy glycinin by enzymatic treatment. Adsorption and foaming characteristics. Food Hydrocoll 2009. [DOI: 10.1016/j.foodhyd.2008.03.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
32
|
Kotsmar C, Grigoriev DO, Xu F, Aksenenko EV, Fainerman VB, Leser ME, Miller R. Equilibrium of adsorption of mixed milk protein/surfactant solutions at the water/air interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13977-13984. [PMID: 19053640 DOI: 10.1021/la802335g] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ellipsometry and surface profile analysis tensiometry were used to study and compare the adsorption behavior of beta-lactoglobulin (BLG)/C10DMPO, beta-casein (BCS)/C10DMPO and BCS/C12DMPO mixtures at the air/solution interface. The adsorption from protein/surfactant mixed solutions is of competitive nature. The obtained adsorption isotherms suggest a gradual replacement of the protein molecules at the interface with increasing surfactant concentration for all studied mixed systems. The thickness, refractive index, and the adsorbed amount of the respective adsorption layers, determined by ellipsometry, decrease monotonically and reach values close to those for a surface covered only by surfactant molecules, indicating the absence of proteins from a certain surfactant concentration on. These results correlate with the surface tension data. A continuous increase of adsorption layer thickness was observed up to this concentration, caused by the desorption of segments of the protein and transforming the thin surface layer into a rather diffuse and thick one. Replacement and structural changes of the protein molecules are discussed in terms of protein structure and surface activity of surfactant molecules. Theoretical models derived recently were used for the quantitative description of the equilibrium state of the mixed surface layers.
Collapse
Affiliation(s)
- C Kotsmar
- Max Planck Institute of Colloids and Interfaces, 14476 Potsdam-Golm, Germany.
| | | | | | | | | | | | | |
Collapse
|
33
|
Reis PM, Raab TW, Chuat JY, Leser ME, Miller R, Watzke HJ, Holmberg K. Influence of Surfactants on Lipase Fat Digestion in a Model Gastro-intestinal System. FOOD BIOPHYS 2008; 3:370-381. [PMID: 20401181 PMCID: PMC2854607 DOI: 10.1007/s11483-008-9091-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 05/21/2008] [Indexed: 11/29/2022]
Abstract
In the present study, we use a model gastro-intestinal system to study the influence of different food-grade surface-active molecules (Sn-2 monopalmitin, beta-lactoglobulin, or lysophosphatodylcholine) on lipase activity. The interfacial activity of lipase and surfactants are assessed with the pendant drop technique, a commonly used tensiometry instrument. A mathematical model is adopted which enables quantitative determination of the composition of the water-oil interface as a function of bulk surfactant concentration in the water-oil mixtures. Our results show a decrease in gastric lipolysis when interfacially active molecules are incorporated into a food matrix. However, only the Sn-2 monopalmitin caused a systematic decrease in triglyceride hydrolysis throughout the gastro-intestinal tract. This effect is most likely due to exclusion of both lipase and triglyceride from the water-oil interface together with a probable saturation of the solubilization capacity of bile with monoglycerides. Addition of beta-lactoglobulin or lysophopholipids increased the hydrolysis of fat after the gastric phase. These results can be attributed to an increasing interfacial area with lipase and substrate present at the interface. Otherwise, beta-lactoglobulin, or lysophopholipids reduced fat hydrolysis in the stomach. From the mathematical modeling of the interface composition, we can conclude that Sn-2 monopalmitin can desorb lipase from the interface, which, together with exclusion of substrate from the interface, explains the gradually decreased triglyceride hydrolysis that occurs during the digestion. Our results provide a biophysics approach on lipolysis that can bring new insights into the problem of fat uptake.
Collapse
Affiliation(s)
- Pedro M. Reis
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland
- Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Thomas W. Raab
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland
| | - Jean Y. Chuat
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland
| | | | - Reinhard Miller
- Max-Planck-Institut für Kolloid-und Grenzflächenforschung, Max-Planck-Campus, D-14476 Golm, Germany
| | | | - Krister Holmberg
- Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| |
Collapse
|
34
|
He Q, Zhang Y, Lu G, Miller R, Möhwald H, Li J. Dynamic adsorption and characterization of phospholipid and mixed phospholipid/protein layers at liquid/liquid interfaces. Adv Colloid Interface Sci 2008; 140:67-76. [PMID: 18279818 DOI: 10.1016/j.cis.2007.12.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 08/16/2007] [Accepted: 12/17/2007] [Indexed: 10/22/2022]
Abstract
Drop profile analysis tensiometry is applied to study the adsorption dynamics of phospholipids, proteins and phospholipid/protein mixtures at liquid/liquid interfaces. Measurements of the dynamic interfacial tension of phospholipid layers give information on the adsorption mechanism and the structure of the adsorption layer. The equilibrium and dynamic adsorption of pure protein solutions, i.e. human serum album (HSA), beta-lactoglobulin (beta-LG), beta-casein (beta-CA), can be explained well by the thermodynamic model of Frumkin and the diffusion-controlled adsorption theory. The adsorption behavior from mixed phospholipid/protein solutions was also investigated in terms of dynamic interfacial tensions. Interestingly, a "skin-like" folded film of pure protein or phospholipid/protein complex layers can be observed at curved surfaces at the water/oil interfaces. The addition of phospholipids accelerates the formation of the folded structure at the drop surface through co-adsorption of proteins.
Collapse
|
35
|
Rodríguez Patino JM, Carrera Sánchez C, Rodríguez Niño MR. Implications of interfacial characteristics of food foaming agents in foam formulations. Adv Colloid Interface Sci 2008; 140:95-113. [PMID: 18281008 DOI: 10.1016/j.cis.2007.12.007] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 12/20/2007] [Indexed: 11/29/2022]
Abstract
The manufacture of food dispersions (emulsions and foams) with specific quality attributes depends on the selection of the most appropriate raw materials and processing conditions. These dispersions being thermodynamically unstable require the use of emulsifiers (proteins, lipids, phospholipids, surfactants etc.). Emulsifiers typically coexist in the interfacial layer with specific functions in the processing and properties of the final product. The optimum use of emulsifiers depends on our knowledge of their interfacial physico-chemical characteristics - such as surface activity, amount adsorbed, structure, thickness, topography, ability to desorb (stability), lateral mobility, interactions between adsorbed molecules, ability to change conformation, interfacial rheological properties, etc. -, the kinetics of film formation and other associated physico-chemical properties at fluid interfaces. These monolayers constitute well defined systems for the analysis of food colloids at the micro- and nano-scale level, with several advantages for fundamental studies. In the present review we are concerned with the analysis of physico-chemical properties of emulsifier films at fluid interfaces in relation to foaming. Information about the above properties would be very helpful in the prediction of optimised formulations for food foams. We concluded that at surface pressures lower than that of monolayer saturation the foaming capacity is low, or even zero. A close relationship was observed between foaming capacity and the rate of diffusion of the foaming agent to the air-water interface. However, the foam stability correlates with the properties of the film at long-term adsorption.
Collapse
Affiliation(s)
- Juan M Rodríguez Patino
- Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, C/ Prof. García González, 1, E-41012-Sevilla, Spain.
| | | | | |
Collapse
|
36
|
Reis P, Miller R, Krägel J, Leser M, Fainerman VB, Watzke H, Holmberg K. Lipases at interfaces: unique interfacial properties as globular proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6812-6819. [PMID: 18512870 DOI: 10.1021/la704044k] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The adsorption behavior of two globular proteins, lipase from Rhizomucor miehei and beta-lactoglobulin, at inert oil/water and air/water interfaces was studied by the pendant drop technique. The kinetics and adsorption isotherms were interpreted for both proteins in different environments. It was found that the adopted mathematical models well describe the adsorption behavior of the proteins at the studied interfaces. One of the main findings is that unique interfacial properties were observed for lipase as compared to the reference beta-lactoglobulin. A folded drop with a "skinlike" film was formed for the two proteins after aging followed by compression. This behavior is normally associated with protein unfolding and covalent cross-linking at the interface. Despite this, the lipase activity was not suppressed. By highlighting the unique interfacial properties of lipases, we believe that the presented work contributes to a better understanding of lipase interfacial activation and the mechanisms regulating lipolysis. The results indicate that the understanding of the physical properties of lipases can lead to novel approaches to regulate their activity.
Collapse
Affiliation(s)
- P Reis
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland
| | | | | | | | | | | | | |
Collapse
|
37
|
Postmus BR, Leermakers FAM, Cohen Stuart MA. Self-consistent field modeling of adsorption from polymer/surfactant mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6712-6720. [PMID: 18507409 DOI: 10.1021/la800524d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report on the development of a self-consistent field model that describes the competitive adsorption of nonionic alkyl-(ethylene oxide) surfactants and nonionic polymer poly(ethylene oxide) (PEO) from aqueous solutions onto silica. The model explicitly describes the response to the pH and the ionic strength. On an inorganic oxide surface such as silica, the dissociation of the surface depends on the pH. However, salt ions can screen charges on the surface, and hence, the number of dissociated groups also depends on the ionic strength. Furthermore, the solvent quality for the EO groups is a function of the ionic strength. Using our model, we can compute bulk parameters such as the average size of the polymer coil and the surfactant CMC. We can make predictions on the adsorption behavior of either polymers or surfactants, and we have made adsorption isotherms, i.e., calculated the relationship between the surface excess and its corresponding bulk concentration. When we add both polymer and surfactant to our mixture, we can find a surfactant concentration (or, more precisely, a surfactant chemical potential) below which only the polymer will adsorb and above which only the surfactant will adsorb. The corresponding surfactant concentration is called the CSAC. In a first-order approximation, the surfactant chemical potential has the CMC as its upper bound. We can find conditions for which CMC < CSAC . This implies that the chemical potential that the surfactant needs to adsorb is higher than its maximum chemical potential, and hence, the surfactant will not adsorb. One of the main goals of our model is to understand the experimental data from one of our previous articles. We managed to explain most, but unfortunately not all, of the experimental trends. At the end of the article we discuss the possibilities for improving the model.
Collapse
Affiliation(s)
- Bart R Postmus
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
| | | | | |
Collapse
|
38
|
Drop profile analysis tensiometry with drop bulk exchange to study the sequential and simultaneous adsorption of a mixed β-casein /C12DMPO system. Colloid Polym Sci 2008. [DOI: 10.1007/s00396-008-1872-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
39
|
Interaction of cationic surfactant and anionic polyelectrolytes in mixed aqueous solutions. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.06.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
40
|
Alahverdjieva VS, Grigoriev DO, Fainerman VB, Aksenenko EV, Miller R, Möhwald H. Competitive Adsorption from Mixed Hen Egg-White Lysozyme/Surfactant Solutions at the Air−Water Interface Studied by Tensiometry, Ellipsometry, and Surface Dilational Rheology. J Phys Chem B 2008; 112:2136-43. [DOI: 10.1021/jp074753k] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- V. S. Alahverdjieva
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| | - D. O. Grigoriev
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| | - V. B. Fainerman
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| | - E. V. Aksenenko
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| | - R. Miller
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| | - H. Möhwald
- Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14424 Potsdam, Germany, Medical Physicochemical Centre, Donetsk Medical University, 16 Ilych Avenue, 83003 Donetsk, Ukraine, and Institute of Colloid Chemistry and Chemistry of Water, 42 Vernadsky Avenue, 03680 Kyiv (Kiev), Ukraine
| |
Collapse
|
41
|
Ferri JK, Dong WF, Miller R. Ultrathin free-standing polyelectrolyte nanocomposites: a novel method for preparation and characterization of assembly dynamics. J Phys Chem B 2007; 109:14764-8. [PMID: 16852865 DOI: 10.1021/jp052672n] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a new opportunity for the investigation of the dynamics of electrostatic ultrathin-film assembly and the elucidation of time scales required for layer-by-layer adsorption of polyelectrolytes using a novel pendant drop technique which allows for the synthesis of free-standing nanocomposites. In short, a charged molecular template, i.e., a lipid monolayer, is deposited on a pendant drop and compressed to present a defined surface charge density to the subphase of the drop. The subphase is then cycled alternatively between solutions of polycations, saline, and polyanions by injection and withdrawal of liquid from coaxial capillaries on which the drop was formed, resulting in encapsulation of the drop volume by a polymeric composite membrane. The in situ dynamics of the process are followed by axisymmetric drop shape analysis. As a model, nanocomposites of dimyristoyl phosphatidyl glycerol-(polyallylamine hydrochloride/polystyrene sulfonate)(n=1-3) were prepared. The characteristic time scales for assembly range from 1 to 4 min and increase with film thickness. It is also demonstrated that small-amplitude (>1%) perturbations in the film density during adsorption prolong the assembly. Both these results underscore the nonequilibrium nature of these materials.
Collapse
|
42
|
Rodríguez Patino JM, Rodríguez Niño MR, Carrera Sánchez C. Physico-chemical properties of surfactant and protein films. Curr Opin Colloid Interface Sci 2007. [DOI: 10.1016/j.cocis.2007.06.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
43
|
Yakuninskaya AE, Zorin IM, Bilibin AY, Lin SY, Loglio G, Miller R, Noskov BA. Dynamic properties of the adsorption films of the copolymer of N-isopropylacrylamide and sodium 2-acrylamide-2-methyl-1-propane sulfonate. COLLOID JOURNAL 2007. [DOI: 10.1134/s1061933x07040163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
44
|
|
45
|
Chen DL, Li L, Reyes S, Adamson DN, Ismagilov RF. Using three-phase flow of immiscible liquids to prevent coalescence of droplets in microfluidic channels: criteria to identify the third liquid and validation with protein crystallization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:2255-60. [PMID: 17279722 PMCID: PMC1986632 DOI: 10.1021/la062152z] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This manuscript describes the effect of interfacial tensions on three-phase liquid-liquid-liquid flow in microfluidic channels and the use of this flow to prevent microfluidic plugs from coalescing. One problem in using microfluidic plugs as microreactors is the coalescence of adjacent plugs caused by the relative motion of plugs during flow. Here, coalescence of reagent plugs was eliminated by using plugs of a third immiscible liquid as spacers to separate adjacent reagent plugs. This work tested the requirements of interfacial tensions for plugs of a third liquid to be effective spacers. Two candidates satisfying the requirements were identified, and one of these liquids was used in the crystallization of protein human Tdp1 to demonstrate its compatibility with protein crystallization in plugs. This method for identifying immiscible liquids for use as a spacer will also be useful for applications involving manipulation of large arrays of droplets in microfluidic channels.
Collapse
Affiliation(s)
- Delai L Chen
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | | | | | | | | |
Collapse
|
46
|
Reynolds BJ, Ruegg ML, Mates TE, Radke CJ, Balsara NP. Diblock copolymer surfactant transport across the interface between two homopolymers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:9192-200. [PMID: 17042529 DOI: 10.1021/la060580z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Dynamics of adsorption and desorption of a diblock copolymer to an interface between two homopolymers was measured using dynamic secondary-ion mass spectrometry (SIMS). Thin films were constructed consisting of a layer of saturated polybutadiene with 90% 1,2-addition (sPB90), followed by a layer of saturated polybutadiene with 63% 1,2-addition (sPB63), and finally by another layer of the sPB90 homopolymer. A sPB90-sPB63 diblock copolymer was initially included only in the top sPB90 layer of the film at a volume fraction of 0.05. The thin films were annealed at ambient temperature for times ranging between 0.2 and 108 h, and the concentration profiles of the diblock copolymer through the films were measured using SIMS. The dynamics of adsorption and desorption of the diblock copolymer at the two sPB90-sPB63 interfaces was gauged by comparing the different transient concentration profiles. The sorption process was modeled as diffusion in an external field, generated from self-consistent field theory (SCFT). All parameters for the model were determined independently. Although the model neglects the dynamics of conformational change, experimental results matched theory very well.
Collapse
Affiliation(s)
- Benedict J Reynolds
- Department of Chemical Engineering, University of California, Berkeley, California 94720, USA
| | | | | | | | | |
Collapse
|
47
|
Sanchez CC, Fernandez MC, Rodríguez Niño MR, Rodríguez Patino JM. Thermodynamic and dynamic characteristics of monoglyceride monolayers penetrated by beta-casein. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:4215-24. [PMID: 16618167 DOI: 10.1021/la053506+] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In this work, we have analyzed the dynamics of the penetration of beta-casein into monoglyceride monolayers (monopalmitin and monoolein) and the structural, dilatational, and topographical characteristics of mixed films formed by monoglyceride penetrated by beta-casein. Different complementary experimental techniques [dynamic tensiometry, surface film balance, Brewster angle microscopy (BAM), and surface dilatational rheology] have been used, maintaining the temperature constant at 20 degrees C and the pH at 7. The surface pressure of the monoglyceride monolayer at the beginning of the penetration process (at pi(i)MP and pi(i)MO for monopalmitin and monoolein, respectively) was the variable studied. beta-Casein can penetrate into a spread monoglyceride monolayer at every surface pressure. The penetration of beta-casein into the monoglyceride monolayer with a more condensed structure, at the collapse point of the monoglyceride, is a complex process that is facilitated by monoglyceride molecular loss by collapse and/or desorption. However, the structural, topographical, and dilatational characteristics of the monoglyceride penetrated by beta-casein mixed monolayers are essentially dominated by the presence of the monoglyceride (either monopalmitin or monoolein) in the mixed film.
Collapse
Affiliation(s)
- Cecilio Carrera Sanchez
- Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, Calle Prof. García Gonzalez, 1, E-4012 Seville, Spain
| | | | | | | |
Collapse
|
48
|
Mezzenga R, Schurtenberger P, Burbidge A, Michel M. Understanding foods as soft materials. NATURE MATERIALS 2005; 4:729-40. [PMID: 16195765 DOI: 10.1038/nmat1496] [Citation(s) in RCA: 439] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Foods make up some of the most complex examples of soft condensed matter (SCM) with which we interact daily. Their complexity arises from several factors: the intricacy of components, the different aggregation states in which foods are encountered, and the multitude of relevant characteristic time and length scales. Because foodstuffs are governed by the rules of SCM physics but with all the complications related to real systems, the experimental and theoretical approaches of SCM physics have deepened our comprehension of their nature and behaviour, but many questions remain. In this review we discuss the current understanding of food science, by considering established SCM methods as well as emerging techniques and theoretical approaches. With their complexity, heterogeneity and multitude of states, foods provide SCM physics with a challenge of remarkable importance.
Collapse
Affiliation(s)
- Raffaele Mezzenga
- Department of Physics, University of Fribourg, Perolles, Fribourg, CH-1700 Switzerland.
| | | | | | | |
Collapse
|
49
|
Roberts SA, Kellaway IW, Taylor KMG, Warburton B, Peters K. Combined surface pressure-interfacial shear rheology study of the effect of pH on the adsorption of proteins at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:7342-8. [PMID: 16042464 DOI: 10.1021/la050272l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The effect of pH on the adsorption of catalase and lysozyme at the air-water interface has been studied using a combined surface pressure-interfacial shear rheology technique. The results presented show that the rate of development of interfacial phenomena increases as the pH of the subphase approaches the isoelectric point of the protein under investigation. The development of the measured interfacial rheological parameters is due to an increased rate of cross-link formation within the resultant interfacial gel. The formation of the interfacial gels has been modeled using a combination of the Smoluchowski theory for the coagulation of an aerosol or fog and classic rubber elasticity theory. The enhanced rate of cross-link formation at the isoelectric point is a result of an in-surface phase separation brought about by cooperative deionization of the protein molecules near their isoelectric point. Simultaneous measurements of surface pressure and interfacial rheology have enabled us to show that the development of a gel-like interfacial network coincides with observed increases in surface pressure.
Collapse
Affiliation(s)
- Simon A Roberts
- The School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, United Kingdom.
| | | | | | | | | |
Collapse
|