Development and characterization of chitosan-thyme essential oil nanoemulsion films for active packaging of raw chicken drumsticks

Abstract

This study focused on the development and characterization of a bioactive film of chitosan (1.5%, w/v) integrated with a thyme (Thymus vulgaris) essential oil nanoemulsion (TNEO). The biopolymer was applied on raw chicken drumsticks to assess its effectiveness in preserving the quality and safety of meat under refrigeration. Gas chromatography-mass spectrometry (GC-MS/MS) analysis of the thyme essential oil identified key bioactive components, viz. carvacrol (60.18%), m-cymene (22.93%) and thymol (3.24%). The dynamic light scattering (DLS) assay and transmission electron microscopy (TEM) ensured the successful encapsulation and stability of the nanoemulsion. The infusion of thyme nanoemulsion significantly enhanced the morphological features, UV barrier properties, moisture vapor barrier properties, and flexibility of chitosan film- critical properties, fulfilling the requirements for effective meat packaging. Further, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were performed to analyze the active biopolymers, which ensured the compatibility between nanoemulsion and chitosan matrix. Notably, the film with 2% TNEO exhibited significant antimicrobial activity against Staphylococcus aureus (14.67 ± 0.33 mm) and Escherichia coli (12.67 ± 0.33 mm), as measured through zones of inhibition (ZOI), and also antioxidant properties (40.05 ± 1.19% reactive scavenging activity). When applied to chicken drumsticks, the 2% TNEO film significantly delayed microbial spoilage, inhibited lipid oxidation, and preserved the color attributes of the meat over a 15-day refrigerated storage period compared to no chitosan and TNEO film. From this study, it is concluded that chitosan-thyme nanoemulsion film can be utilized as a highly promising, green active-packaging solution for extending the shelf-life of raw poultry. © 2025 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0)