Physico-chemical and antimicrobial characteristics of novel biodegradable films based on gellan and carboxymethyl cellulose containing rosemary essential oil

The purpose of the current investigation was to produce a novel functional composite biodegradable film by Gellan (Gla) and Carboxymethyl cellulose (CMC) biopolymers containing rosemary essential oils (REO) and evaluate their physicochemical and antimicrobial features. The film containing 5 % REO, due to its better me-chanical properties (UTS = 13.44 +/- 0.30 Mpa and SB = 21.14 +/- 1.15 %) compared to other emulsified samples containing REO, was selected as the optimal film. Furthermore, it had less water vapor permeability (WVP = 6.60 +/- 0.31 (g/mhPa) x 10-8) in comparison to control sample (8.21 +/- 0.10 (g/mhPa) x 10-8) and the best color properties among the samples. The Scanning Electron Microscopy (SEM) images didn't show the phenomenon of agglomeration and point accumulation of REO. Also, 5 % of REO contributed to the increased compactness of the film in comparison to the film without the REO. Based on the results of Fourier-transform infrared spectroscopy (FTIR) spectra, no new chemical bonds were created by adding REO to the biopolymer substrate, and the REO was well dispersed and distributed among the Gla-CMC chains throughout the film substrate. Adding 5 % REO showed antioxidant effects. Considering the antimicrobial tests, all films containing REO had antimicrobial ef-fects against the Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Pseudomonas fluorescens bacterial strains.

Automated summary

The purpose of this study was to produce a novel functional composite biodegradable film by incorporating rosemary essential oils (REO) into Gellan (Gla) and Carboxymethyl cellulose (CMC) biopolymers and evaluate their physical, chemical, and antimicrobial properties. The film containing 5% REO was selected as the optimal film due to its superior mechanical properties, lower water vapor permeability, and better color properties compared to other emulsified samples. The addition of 5% REO showed antioxidant effects and exhibited antimicrobial properties against various bacterial strains.