Recyclable Bilayer Active Food Packaging Films: Corona-Treated LDPE Coated with Gelatin/Glycerol and Carvacrol or Eugenol@Natural Zeolite Nanohybrids

Abstract

This study reports novel bilayer active packaging films based on corona-treated low-density polyethylene (LDPE) coated with gelatin/glycerol (Gel/Gl) incorporating eugenol@natural zeolite (EG@NZ) or carvacrol@natural zeolite (CV@NZ) nanohybrids. All Gel-based films demonstrated oxygen transmission rates below the instrument detection limit (<0.008 cc O2/m2/day), overcoming the poor oxygen barrier of LDPE (1530 cc O2/m2/day). CV@NZ films exhibited strong diffusible antimicrobial activity against Staphylococcus aureus (18–20 mm inhibition zones) and effectively reduced microbial growth in fresh ham during refrigerated storage (TVC < 3 log CFU/g for 28 days). The bilayer design enables recyclability through removal of the water-soluble Gel layer, allowing recovery of the LDPE substrate. Overall, the developed films combine improved oxygen barrier properties, tunable bioactivity, and compatibility with conventional processing methods.