Molecular flexibility in wheat gluten proteins submitted to heating

Area of Science:

• Food science and technology
• Biophysics

Background:

• Prolamin proteins form the viscoelastic network in wheat dough.
• Understanding protein dynamics is crucial for dough functionality.

Purpose of the Study:

• To investigate the molecular dynamics of gluten proteins using Electron Spin Resonance (ESR).
• To determine the effect of temperature on gluten's molecular flexibility and compare it to purified subunits.

Main Methods:

• Preparation of non-prolamin depleted gluten.
• Electron Spin Resonance (ESR) spectroscopy with spin labeling of cysteine residues.
• Analysis of protein dynamics across a temperature range (5–90°C) using saturation transfer ESR.

Main Results:

• Gluten spectra indicated at least two distinct protein mobility populations.
• Heating induced a reversible shift from slower to faster moving spin labels, following Arrhenius behavior.
• Urea treatment mimicked the heat-induced modifications in gluten, unlike purified glutenin subunits.

Conclusions:

• Gluten's viscoelasticity is linked to complex protein dynamics with distinct mobile populations.
• Temperature reversibly alters gluten's molecular flexibility, a phenomenon not observed in purified subunits.
• Urea's effect suggests disruption of protein interactions similar to thermal denaturation.