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(144) Production(s) de IN M.
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Adsorption and structure of wheat proteins film at the air-water interface
Auteur(s): Poirier A., Banc A., Stocco A., In M., Ramos L.
Conference: 3rd Food Structure Functionality Forum Symposium (Montreal, CA, 2018-06-04)
Ref HAL: hal-01912810_v1
Exporter : BibTex | endNote
Résumé: Gliadins are edible wheat storage proteins well known for their surface active properties. In this paper, we present experimental results on the interfacial properties of acidic solutions of gliadin studied over 5 decades of concentrations, from 0.001 to 110 g/L. Dynamic pendant drop tensiometry reveals that the surface pressure of gliadin solutions builds up in a multistep process. The series of curves of the time evolution of collected at different bulk protein concentrations C can be merged onto a single master curve when is plotted as a function of t where t is the time elapsed since the formation of the air/water interface and is a shift parameter that varies with C as a power law with an exponent 2. The existence of such time-concentration superposition, which we evidence for the first time, indicates that the same mechanisms govern the surface tension evolution at all concentrations and are accelerated by an increase of the bulk concentration. The scaling of with C is consistent with a kinetic of adsorption controlled by the diffusion of the proteins in the bulk. Moreover, we show that the proteins adsorption at the air/water interface is kinetically irreversible. Correlated evolutions of the optical and elastic properties of the interfaces, as probed by ellipsometry and surface dilatational rheology respectively, provide a consistent physical picture of the building up of the protein interfacial layer. A progressive coverage of the interface by the proteins occurs at low . This stage is followed, at higher , by conformational rearrangements of the protein film, which are identified by a strong increase of the dissipative viscoelastic properties of the film concomitantly with a peculiar evolution of its optical profile that we have rationalized. In the last stage, at even higher surface pressure, the adsorption is arrested; the optical profile is not modified while the elasticity of the interfacial layer dramatically increases with the surface pressure, presumably due to the film ageing.
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Nano-porous structures via self-assembly of amphiphilic triblock copolymers: influence of solvent and molecular weight
Auteur(s): Nehache Sabrina, Semsarilar M., In M., Dieudonne-George P., Lai Kee Him J., Bron P., Quemener D.
(Article) Publié:
Journal Of Polymer Science Part A: Polymer Chemistry, vol. 9 p.193-202 (2018)
Ref HAL: hal-01680368_v1
DOI: 10.1039/c7py01853c
WoS: 000418645100006
Exporter : BibTex | endNote
4 Citations
Résumé: Control of film structures made from a polystyrene-polystyrene sodium sulfonate-polystyrene (PS-PNaSS-PS) copolymer micellar solution is investigated in a THF/water mixture. Four different copolymers (varying molecular weights) are synthesised via RAFT (Reversible Addition Fragmentation chain Transfer) polymerisation. Depending on parameters such as copolymer molecular weight, solvent composition and copolymer concentration, the PS-PNaSS-PS triblock self-assembles into different morphologies in solution and dry state. The effect of each parameter is investigated using characterization techniques such as AFM, TEM, Cryo-TEM, SEM and SAXS. The morphologies obtained for PS-PNaSS-PS are found to be extremely sensitive when the water content of the micellar solution is low. Among the structures observed, a highly ordered nano-porous film is obtained using a PS10k-PNaSS6k-PS10k triblock copolymer solution containing 3.0 wt% of water. This micellar solution is used to prepare a porous membrane for filtration applications. Pure water filtration data suggest a pore size in the range of ultrafiltration, making these membranes attractive for applications in the food industry, for bacteria, virus and protein removal.
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Multistep building of a soft plant protein film at the air-water interface
Auteur(s): Poirier A., Banc A., Stocco A., In M., Ramos L.
(Article) Publié:
Journal Of Colloid And Interface Science, vol. 526 p.337 - 346 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01788790_v1
PMID 29751267
DOI: 10.1016/j.jcis.2018.04.087
WoS: 000436900400034
Exporter : BibTex | endNote
20 Citations
Résumé: Gliadins are edible wheat storage proteins well known for their surface active properties. In this paper, we present experimental results on the interfacial properties of acidic solutions of gliadin studied over 5 decades of concentrations, from 0.001 to 110 g/L. Dynamic pendant drop tensiometry reveals that the surface pressure of gliadin solutions builds up in a multistep process. The series of curves of the time evolution of collected at different bulk protein concentrations C can be merged onto a single master curve when is plotted as a function of t where t is the time elapsed since the formation of the air/water interface and is a shift parameter that varies with C as a power law with an exponent 2. The existence of such time-concentration superposition, which we evidence for the first time, indicates that the same mechanisms govern the surface tension evolution at all concentrations and are accelerated by an increase of the bulk concentration. The scaling of with C is consistent with a kinetic of adsorption controlled by the diffusion of the proteins in the bulk. Moreover, we show that the proteins adsorption at the air/water interface is kinetically irreversible. Correlated evolutions of the optical and elastic properties of the interfaces, as probed by ellipsometry and surface dilatational rheology respectively, provide a consistent physical picture of the building up of the protein interfacial layer. A progressive coverage of the interface by the proteins occurs at low . This stage is followed, at higher , by conformational rearrangements of the protein film, which are identified by a strong increase of the dissipative viscoelastic properties of the film concomitantly with a peculiar evolution of its optical profile that we have rationalized. In the last stage, at even higher surface pressure, the adsorption is arrested; the optical profile is not modified while the elasticity of the interfacial layer dramatically increases with the surface pressure, presumably due to the film ageing.
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Interfacial behavior of plant based proteins
Auteur(s): Poirier A., Banc A., Stocco A., In M., Ramos L.
Conference: Physics for Food Manufacturing (Edimbourg, GB, 2018-01-11)
Ref HAL: hal-01715256_v1
Exporter : BibTex | endNote
Résumé: With the demography growth, there is a huge pressure on protein demand, and the development of plant based proteins is required for a future sustainable food production. Plant proteins are efficient to stabilize interfaces in foams or emulsions, and the understanding of physical mechanisms at the origin of their interfacial behavior is important to develop new products. We investigate the adsorption of wheat grains (gliadin) and sunflower seeds (helianthinin) proteins, at air-water and oil-water interfaces, respectively. A combination of tensiometry, dilatational viscoelasticity and ellipsometry measurements is used to determine the adsorption mechanisms, and characterize the structure and properties of the interfacial protein films formed with different bulk protein concentrations. We demonstrate that a diffusion-controlled adsorption occurs at low bulk protein concentration for helianthinin whereas this mechanism occurs whatever the bulk concentration for gliadins. Surface pressure-induced film relaxation through conformation changes of proteins at the air-water interface is identified for gliadin whereas surface aggregation is observed at high helianthinin concentration. Overall, our experimental results highlight that structural flexibility of proteins appears as a key factor for their interfacial activity.
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Micellisation électrostatique de copolymères à blocs double-hydrophiles
Auteur(s): Phimphachanh A., Mathonnat M., Pinaud Julien, Lacroix-Desmazes Patrick, Destarac Mathias, Cottet Hervé, Chamieh Joseph, Leclercq Laurent, Marcotte Nathalie, In M., Gerardin Corine
Conference: 45èmes journées d'études des polymères (Gravelines, FR, 2017-10-01)
Texte intégral en Openaccess :
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Electrostatic micellization of double-hydrophilic block copolymers
Auteur(s): Phimphachanh A., Mathonnat M., Pinaud Julien, Lacroix-Desmazes Patrick, Destarac Mathias, Cottet Herve, Marcotte Nathalie, Gerardin Corine, In M.
Conference: European Polymer Federation Congress (Lyon, FR, 2017-07-02)
Texte intégral en Openaccess :
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