Novel Bioactive Composite Films Based on Pectin-Nanocellulose-Synergistic Triple Essential Oils: Development and Characterization

This study aimed to formulate and characterize the bioactive pectin-nanocellulose-based films carrying a synergistic mixture of shirazi thyme ( Zataria multiflora ), cinnamon ( Cinnamomum zeylanicum ), and clove ( Syzygium aromaticum ) essential oils (EOs). Four bioactive nanocomposite films including two different synergistic EO combinations in high (HC) and low concentrations (LC) were developed. Physical, thermal, mechanical, and biological properties of the prepared films were investigated. The moisture content, moisture absorption, and water vapor permeability of the bioactive films with high concentrations of EOs showed an average reduction by 16.3%, 64.5%, and 35.8%, respectively ( p < 0.05). Additionally, increasing the EO concentration improved the elongation at break from 44.96 to 52.5% and from 43.73 to 53.81% in the bioactive films with double and triple EO combinations, respectively. However, analysis of the thermal properties indicated that the incorporation of EOs in high concentrations decreased the melting temperatures ( T m ) of the bioactive films significantly from 165.37 °C in the control film to 156.09 and 155.4 °C in the thyme/cinnamon (HC) and thyme/cinnamon/clove (HC) bioactive films, respectively ( p ≤ 0.05). Thyme/cinnamon/clove (HC) film presented the highest antioxidant and antimicrobial effects with the inhibition zone of 314, 200.96, and 113.04 mm against S. aureus , E. coli , and P. fluorescens bacteria. In brief, the incorporation of nanocellulose and synergistic EOs into pectin-based films leads to the development of water-resistant bioactive films and boosts the antibacterial and antioxidant properties that have the potential to be used in the food packaging. Graphical Abstract