Pectin-based films with thyme essential oil: production, characterization, antimicrobial activity, and biodegradability

Abstract

This work aimed to incorporate thyme essential oil into films composed of pectin to provide antimicrobial action to them. The effect of adding essential oil on the films' mechanical, physical-chemical, and barrier properties and their degradability was evaluated. Essential oil addition was possible by using Tween^® 20 as an emulsifier, and it was possible to observe antimicrobial activity in the films containing 1.0 wt.% and 2.0 wt.% essential oil. The films containing thyme essential oil were more elastic and thicker but less resistant, with high permeability to water vapor and more hydrophilic relative to other formulations. Scanning electron microscopy analysis showed the presence of heterogeneities in the formulations with essential oil. The films produced using the optimized formulation (30 wt.% glycerol, 1.0 wt.% thyme essential oil, and 0.5 wt.% Tween^® 20 relative to pectin mass) degraded entirely after 24 days of exposure to standard soil.

Keywords:
active packaging; biological activity; biopolymer; terpenes