Preparation and characterization of biocomposite chitosan film containing Perilla frutescens (L.) Britt. essential oil

Abstract

In the present study, biocomposite films with incorporated Perilla frutescens (L.) Britt. essential oil (PEO) were prepared using the solvent casting method. Perilla essential oil concentrations at 0.2%, 0.6%, and 1.0% (v/v) had a significant effect on the physical, chemical, and antibacterial activity of the films. Films with PEO exhibited a significant decrease (p < 0.05) in tensile strength (TS), elongation at break (%E), water vapor permeability (WVP), water solubility (WS), and swelling ratio (SR). The amounts of PEO had a significant effect on the WVP, WS, and SR but had no significant effect on the TS and%E (p < 0.05). Addition of PEO to the chitosan film significantly improved the ultraviolet–visible-light barrier of the film. The antimicrobial properties of the films were significantly enhanced by PEO. An increased roughness of the biocomposite films with added PEO was shown by scanning electron microscopy. Fourier transform infrared spectroscopy showed new interactions in the biocomposite films. X-ray diffraction measurements confirmed that the films with PEO have more dense crystalline domains in comparison with the pure chitosan film samples. Furthermore, the thermal stability of the film decreased upon PEO addition, and the weight loss of films with PEO increased with increasing amount of PEO, as suggested by thermogravimetric analyses. The biocomposite films with incorporated PEO demonstrated good activity against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, showing inhibition zone diameters (mm) of 24.563 ± 0.021 mm, 20.153 ± 0.006 mm, and 23.427 ± 0.015 mm, respectively. Overall, the biocomposite chitosan film with added PEO have potential application for food preservation as a biodegradable and ecofriendly packaging material.