Phenolic-Enriched Pullulan Coatings: Molecular Interactions and Functional Properties for Active Food Packaging...

Area of Science:

• Food Science and Technology
• Materials Science
• Polymer Chemistry

Background:

• Active coatings for food packaging are crucial for extending shelf life and ensuring food safety.
• Renewable polymer-based colloidal coatings are gaining traction but require further exploration compared to traditional films.
• Understanding the link between colloidal properties and film performance is vital for effective coating design.

Purpose of the Study:

• To develop and characterize sustainable, active colloidal coatings using pullulan functionalized with yerba mate (YE) and chestnut wood (WE) extracts.
• To establish a structure-property relationship by linking liquid formulation characteristics to formed film properties.
• To evaluate the functional performance of these coatings for food-packaging applications.

Main Methods:

• Green ultrasound-assisted aqueous extraction of polyphenols from yerba mate and chestnut wood.
• Preparation of pullulan-polyphenol colloidal dispersions and characterization of their stability (ζ-potential, PDI).
• Analysis of film properties including water contact angle, surface free energy, UV shielding, antioxidant capacity, and antibacterial activity.

Main Results:

• Pullulan-YE/WE dispersions showed enhanced colloidal stability (ζ ≈ -25 mV; PDI ≈ 0.16).
• Formed films exhibited reduced water contact angle and increased surface free energy, indicating improved interfacial performance.
• Coatings demonstrated significant UV shielding, potent antioxidant activity, and notable antibacterial efficacy against *Staphylococcus aureus*.

Conclusions:

• A structure-property-driven approach is essential for rational design of functional biopolymer coatings.
• Pullulan-polyphenol dispersions offer a promising route to biodegradable, multifunctional active layers for sustainable food packaging.
• The developed coatings provide a viable alternative to conventional packaging materials, enhancing food safety and sustainability.