Polymerization Kinetics of Wheat Gluten upon Thermosetting. A Mechanistic Model

Abstract

Size exclusion high-performance liquid chromatography analysis was carried out on wheat gluten-glycerol blends subjected to different heat treatments. The elution profiles were analyzed in order to follow the solubility loss of protein fractions with specific molecular size. Owing to the known biochemical changes involved during the heat denaturation of gluten, a mechanistic mathematical model was developed, which divided the protein denaturation into two distinct reaction steps: (i) reversible change in protein conformation and (ii) protein precipitation through disulfide bonding between initially SDS-soluble and SDS-insoluble reaction partners. Activation energies of gluten unfolding, refolding, and precipitation were calculated with the Arrhenius law to 53.9 kJ x mol(-1), 29.5 kJ x mol(-1), and 172 kJ x mol(-1), respectively. The rate of protein solubility loss decreased as the cross-linking reaction proceeded, which may be attributed to the formation of a three-dimensional network progressively hindering the reaction. The enhanced susceptibility to aggregation of large molecules was assigned to a risen reaction probability due to their higher number of cysteine residues and to the increased percentage of unfolded and thereby activated proteins as complete protein refolding seemed to be an anticooperative process.

Overall and Local Bread Expansion, Mechanical Properties, and Molecular Structure During Bread Baking: Effect of Emulsifying Starches

“…2b) was observed (p > 0.05), being the lowest at 40°C regardless of the dough system (CONTROL or OSA). This is explained by protein macromolecules unfolding which increases the dough flow ability (Domenek et al 2002;Cristina M. Rosell and Foegeding 2007;Hayta and Schofield 2004). The maximum value of J max at 40°C could be attributed to a decrease in elasticity strength.…”

“…The effects of heat treatment on dough rheology in this period arose from two phenomena taking place at the molecular level: conformational changes of gluten proteins and starch gelatinization (melting of crystallites accompanied by water sorption), both affected by the water availability. The conformational changes within the gluten matrix comprised of gliadin and glutenin unfolding, resulting in the exposition of hydrophobic protein zones which ultimately stimulate new hydrophobic interactions, the reorganization of disulfide bonds and finally protein aggregation (Domenek et al 2002). Consequently, an increase in the dough rigidity in this phase of processing Table 3.…”

Dynamic mechanical analysis of the multiple glass transitions of plasticized wheat gluten biopolymer

“…34 The gliadin and glutenin content of the samples were determined by size exclusion high performance liquid chromatography (SE-HPLC). The samples were prepared as described by Domenek et al 35 Briefly, the samples were first extracted in the presence of a surfactant, sodium dodecyl sulfate (SDS), resulting in the solubilization of monomeric gliadins and part of the polymeric glutenins. Then, a second extraction is performed by adding dithioerythriol (DTE), a reducing agent able to disrupt the disulfide bonds and to solubilize the resulting glutenin subunits.…”

Environmental-Friendly Biodegradable Polymers and Composites

“…It is well known that the mechanical properties of protein-based materials correlate with the density of the three-dimensional network formed during processing through disulfide-bond crosslinking (Domenek et al, 2002;Shewry & Tatham, 1997). This density increases with the processing temperature and duration, resulting in higher tensile strength and Young's modulus while elongation at break decreases .…”