Antimicrobial Packaging for Plum Tomatoes Based on ZnO Modified Low-Density Polyethylene

Area of Science:

• Materials Science
• Food Science
• Nanotechnology

Background:

• Polyethylene is a widely used food packaging material due to industry inertia towards new technologies.
• Modifying existing polyethylene films is more feasible than adopting entirely new packaging solutions.
• Incorporating antimicrobial agents into polyethylene can impart antibacterial properties.

Purpose of the Study:

• To develop novel composite films with enhanced antibacterial and UV-blocking properties for food packaging.
• To investigate the effect of incorporating zinc oxide (ZnO) nanoparticles into low-density polyethylene.
• To evaluate the antimicrobial efficacy, physical properties, and food preservation capabilities of the developed composite films.

Main Methods:

• Composite films were prepared by melt mixing low-density polyethylene with varying concentrations of ZnO nanoparticles (up to 5%) at 150 °C for 10 minutes.
• Homogeneous dispersion of ZnO nanoparticles was confirmed using Fourier transform infrared microscopy and scanning electron microscopy.
• Antimicrobial activity, UV-Vis transmittance, mechanical properties, thermal stability, and food preservation efficacy were evaluated.

Main Results:

• Highly homogenous composite films with up to 5% ZnO were successfully produced.
• The films exhibited good transparency in the visible spectrum and excellent UV barrier properties (transmittance < 5%).
• Antimicrobial and antibiofilm activity against Gram-positive and Gram-negative bacteria was observed starting from 1% ZnO.
• Optimal mechanical barrier properties were achieved with 3% ZnO, and thermal stability increased by over 100 °C.
• The composite films successfully preserved plum tomatoes for up to 14 days.

Conclusions:

• ZnO nanoparticle-reinforced polyethylene composite films offer a promising solution for enhancing food packaging safety and quality.
• These films provide effective antimicrobial protection, UV shielding, and improved thermal and mechanical properties.
• The developed packaging material demonstrates significant potential for extending the shelf life of perishable food products.