Eucalyptus oil-loaded nanocarriers composite films to enhance the shelf life of cheese

Abstract

This study developed an environmentally friendly, antimicrobial active food packaging material to extend the shelf life of cheese. Poly(lactic acid) and poly(butylene adipate-co-terephthalate) (PBAT) composite films were incorporated with 1%, 3%, 7%, and 10% (w/w) eucalyptus oil and 0.2% (w/w) titanium dioxide. The physicochemical properties, including optical and mechanical characteristics, surface hydrophobicity, and chemical composition, were evaluated. The films\u27 antimicrobial efficacy against Staphylococcus aureus and Escherichia coli, biofilm inhibition, and cheese preservation performance were assessed. Results indicated that adding eucalyptus oil reduced tensile strength by 35.6%, while enhancing UV-light barrier properties and increasing yellowness. Notably, biofilm inhibition improved from 21% to 92% with increasing eucalyptus oil concentration, and the 10% (w/w) composite film exhibited the highest antimicrobial activity, completely inhibiting E. coli growth. Furthermore, cheese wrapped in this film showed no microbial growth, limiting weight loss to 1.47% over 12 days, compared to 9.30% in the control sample. The water contact angle (WCA) increased from 58.93° to 71.66°, confirming improved surface hydrophobicity, while UV transmittance at 280 nm was reduced to 0.00%, demonstrating superior light-blocking capacity. These findings demonstrate that PLA/PBAT-TiO2-eucalyptus oil (10% w/w) composite films offer promising applications in active food packaging, effectively extending the shelf life of cheese