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SUMMARY:Contr. talk - Understanding gelation of gluten proteins thanks to 
 neutron and X-ray scattering
DTSTART;VALUE=DATE-TIME:20210610T080000Z
DTEND;VALUE=DATE-TIME:20210610T082000Z
DTSTAMP;VALUE=DATE-TIME:20260529T221133Z
UID:indico-contribution-1110@lindico453.srv.lu.se
DESCRIPTION:Speakers: Laurence Ramos ()\nThe origin of the unique rheologi
 cal properties of wheat gluten\, the water-insoluble protein fraction of w
 heat grain\, is crucial in bread-making processes and questions scientists
  since the 18th\ncentury. Gluten is a complex mixture of two families of p
 roteins\, monomeric gliadins (Gli) and polymeric glutenins (Glu). To bette
 r understand the respective role of the different classes of proteins in t
 he supramolecular structure of gluten and its link to the material propert
 ies\, we have developed model gluten systems comprising controlled amounts
  of Gli and Glu in food-grade binary solvents [1]. Using contrast variatio
 n techniques and small-angle neutron scattering\, we have evidenced in\ngl
 uten gels the presence of distinct regions of typical size several tens of
  nm\, which arise from the preferential interaction of Glu polymers throug
 h a tight network of non-exchangeable intermolecular hydrogen bonds\, at t
 he origin of the gelation of gluten [3]. In addition\, we have used time-r
 esolved synchrotron ultra-small X-ray scattering to quantitatively probe t
 he dynamics of liquid-liquid phase separation (LLPS) in gluten protein sus
 pensions following a temperature quench [4]. Fluid viscoelastic samples de
 pleted in polymer Glu phase separate\nfollowing a spinodal decomposition p
 rocess\, with a coarsening resulting from a competition between thermodyna
 mics and transport. Anomalous phase-separation dynamics is by contrast mea
 sured for gluten gels rich in Glu\, due to elastic constraints\, illustrat
 ing the role of viscoelasticity in the dynamics of LLPS in protein dispers
 ions. Additional experiments conducted by changing the solvent\, from pure
  water (a bad solvent for gluten proteins) to ethanol/water (60/40 v/v) (a
  good solvent for gluten proteins) confirm the subtle interplay between ph
 ase-separation and viscoelasticity in gluten proteins gels [5].\n[1] Dahes
 h et al. Polymeric assembly of gluten proteins in an aqueous ethanol solve
 nt. J Phys Chem B 118\, 11065 (2014).\n[2] Banc et al. Small angle neutron
  scattering contrast variation reveals heterogeneities of interactions in 
 protein gels. Soft Matter 12\, 5340 (2016).\n[3] Dahesh et al. Spontaneous
  gelation of wheat gluten proteins in a food grade solvent. Food Hydrocoll
 oids\, 52\, 1 (2016).\n[4] Banc et al. Phase separation dynamics of gluten
  protein mixtures. Soft Matter 15\, 6160 (2019).\n[5] Costanzo et al. Tail
 oring the viscoelasticity of polymer gels of gluten proteins through solve
 nt quality. Submitted (2020)\n\nhttps://lindico453.srv.lu.se/event/159/con
 tributions/1110/
LOCATION:Online on Zoom
URL:https://lindico453.srv.lu.se/event/159/contributions/1110/
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