Multi-scale structural and oxidative evolution of wheat gluten during baking-like dry heating

Area of Science:

• Food Science
• Materials Science
• Biochemistry

Background:

• Wheat gluten (WG) is a complex protein network essential for baked goods.
• Understanding its structural evolution under heat is critical for food processing.

Purpose of the Study:

• To investigate the structural and functional changes in wheat gluten during baking-like dry heating.
• To elucidate the relationship between thermal unfolding, disulfide exchange, and oxidative modifications in WG.

Main Methods:

• Multiscale analyses including dynamic rheology, thiol/disulfide quantification (DTNB), oxidation markers (carbonyl content), and scanning electron microscopy.
• Controlled dry heating of wheat gluten at temperatures ranging from 95°C to 180°C for 0-25 minutes.

Main Results:

• Mild heating (95°C) caused limited loosening and a slight increase in free sulfhydryl groups without significant crosslinking.
• Moderate heating (130-155°C) enhanced disulfide reshuffling and network reinforcement, increasing storage modulus (G') by 2.3-fold and reducing surface hydrophobicity.
• Severe heating (≥180°C) resulted in protein over-oxidation (elevated carbonyls), leading to network solidification and loss of resilience.

Conclusions:

• Wheat gluten exhibits temperature-dependent transitions in network structure and properties during dry heating.
• Disulfide exchange and oxidation are key mechanisms governing WG network evolution under thermal stress.
• Findings provide mechanistic insights for optimizing high-temperature grain processing by controlling WG aggregation and oxidation.