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Phase separation dynamics of gluten protein mixtures 
Auteur(s): Banc A., Pincemaille J., Costanzo S., Chauveau E., Appavou Marie-Sousai, Morel Marie Helene, Menut Paul, Ramos L.
(Article) Publié:
Soft Matter, vol. 15 p.6160-6170 (2019)
Texte intégral en Openaccess : 
Ref HAL: hal-02267857_v1
DOI: 10.1039/C9SM00966C
WoS: 000477986500011
Exporter : BibTex | endNote
2 Citations
Résumé: We investigate by time-resolved synchrotron ultra-small X-ray scattering the dynamics of liquid–liquid phase-separation (LLPS) of gluten protein suspensions following a temperature quench. Samples at a fixed concentration (237 mg ml−1) but with different protein compositions are investigated. In our experimental conditions, we show that fluid viscoelastic samples depleted in polymeric glutenin phase-separate following a spinodal decomposition process. We quantitatively probe the late stage coarsening that results from a competition between thermodynamics that speeds up the coarsening rate as the quench depth increases and transport that slows down the rate. For even deeper quenches, the even higher viscoelasticity of the continuous phase leads to a “quasi” arrested phase separation. Anomalous phase-separation dynamics is by contrast measured for a gel sample rich in glutenin, due to elastic constraints. This work illustrates the role of viscoelasticity in the dynamics of LLPS in protein dispersions.
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Methods for Screening Cloud Point Temperatures
Auteur(s): Pincemaille J., Banc A., Chauveau E., Fromental J.-M., Ramos L., Morel Marie-Hélène, Menut P.
(Article) Publié:
Food Biophysics, vol. 13 p.422-431 (2018)
Ref HAL: hal-01908982_v1
DOI: 10.1007/s11483-018-9548-1
WoS: WOS:000448509200010
Exporter : BibTex | endNote
4 Citations
Résumé: A novel and simple method for the measurement of cloud point temperatures of solutions is presented. Cloud point determination , which is currently used to establish the phase diagrams of protein solutions, is indicative of proteins interactions and constitutes a useful tool for food products engineering. We describe a novel experimental setup that allows screening of a large number of physical-chemical conditions in one measurement and the determination of cloud point temperatures both above and below ambient temperature. We use a simple method to avoid solvent evaporation and condensation, so that the setup can be used for solutions prepared with a volatile solvent. We present the operating parameter range and the precision of the measurement. The optical properties of the system are calibrated with solutions of known transmittance, and the determination of cloud point temperatures is validated on a standard non-ionic surfactant solution. Finally, we demonstrate the efficiency of the method by determining the phase diagram of a wheat protein extract, soluble in a water/ethanol mixture. Complemented with differential scanning calorimetry measurements, the liquid-liquid phase transition can be determined up to a protein concentration of 250 g/L, a range inaccessible with conventional methods for this protein extract.
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