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Abstract
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This study was conducted to investigate the morphological, thermal, mechanical, FTIR, physicochemical
(thickness, humidity, solubility in water and water vapor permeability) and antimicrobial properties of polylactic
acid film (PLA) containing hybrid graphene oxide‑zinc oxide (GO-ZnO: 1.5 % w/v) and Mentha longifolia essential
oil (ML:1 % v/v) on chicken fillet kept in the refrigerator. The studied groups were microbially (total count of
mesophilic aerobic bacteria, psychrotrophic bacteria, Enterobacteriaceae, Staphylococcus aureus, and lactic acid
bacteria), chemically (pH, TVB-N) and sensory (color, odor, and taste) evaluated at 8-day interval (0, 2, 5 and 8).
In the examination of the morphological characteristics, the PLA film had a smooth and uniform surface and the
addition of ML essential oil created a discontinuous structure and the addition of GO-ZnO led to the production of
a denser and more homogeneous film. The presence of GO-ZnO increased the thickness, decreased moisture
content and solubility in water, and added ML essential oil increased moisture content and decreased solubility in
water (p˂0.05). The results of the mechanical evaluation showed that the addition of ML essential oil and GOZnO
reduced elongation at break and tensile strength (p˂0.05). The addition of ML essential oil increased the
thermal resistance and the addition of GO-ZnO decreased the thermal resistance compared to the film containing
ML essential oil. The antimicrobial effect of films containing ML essential oil was confirmed in this study
(p˂0.05). The addition of GO-ZnO did not change the count of any of the microbial groups. TVB-N showed that
groups containing ML essential oil had lower levels of volatile nitrogenous bases than the control group (p˂0.05).
Sensory evaluation of the studied groups showed that chicken fillets packed with films containing ML essential
oil had the highest score in terms of color, smell and taste. The results of the present study showed that PLA fil
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