Polyphenol-plasticized wheat gluten films via formic acid solubilization

Area of Science:

• Materials Science
• Food Science
• Polymer Science

Background:

• Gluten shows potential for sustainable food packaging films.
• Brittleness and moisture sensitivity hinder gluten film applications.
• Formic acid (FA) solubilization offers a method to process gluten.

Purpose of the Study:

• To enhance gluten film properties using polyphenol extracts.
• To investigate the impact of polyphenol structure on film performance.
• To develop tunable gluten-based packaging materials.

Main Methods:

• Gluten films were prepared using formic acid (FA) solubilization.
• Glycerol and polyphenol-rich extracts (green tea extract, grape seed extracts) were incorporated.
• Film properties including tensile strength, ductility, water vapor permeability, and water uptake were evaluated.
• Protein-polyphenol interactions were analyzed using fluorescence quenching and SDS-PAGE.

Main Results:

• Grape seed extract of high polymerization (GSE-HP) increased tensile strength significantly.
• Green tea extract (GTE) improved film ductility.
• Polyphenol structure influenced water interactions, with low water uptake (3.5-6%) and controlled permeability (1.30-4.30 g·mm/m²·day·kPa).
• Non-covalent GTE-protein interactions contrasted with stronger GSE-protein adducts, explaining property trade-offs.

Conclusions:

• Polyphenol polymerization is a key factor in tuning gluten film strength, flexibility, and hydration.
• FA-solubilized gluten films with incorporated polyphenols are promising for multilayer, bio-based packaging.
• This approach offers a method to overcome limitations of gluten-based packaging materials.