Essential Oils and Their Principal Constituents as Antimicrobial Agents for Synthetic Packaging Films

Abstract

Spices and herbal plant species have been recognized to possess a broad spectrum of active constituents that exhibit antimicrobial (AM) activity. These active compounds are produced as secondary metabolites associated with the volatile essential oil (EO) fraction of these plants. A wide range of AM agents derived from EOs have the potential to be used in AM packaging systems which is one of the promising forms of active packaging systems aimed at protecting food products from microbial contamination. Many studies have evaluated the AM activity of synthetic AM and/or natural AM agents incorporated into packaging materials and have demonstrated effective AM activity by controlling the growth of microorganisms. This review examines the more common synthetic and natural AM agents incorporated into or coated onto synthetic packaging films for AM packaging applications. The focus is on the widely studied herb varieties including basil, oregano, and thyme and their EOs.

Effect of pH and Mexican Oregano (Lippia berlandieri Schauer) Essential Oil Added to Carboxymethyl Cellulose and Starch Edible Films on Listeria monocytogenes and Staphylococcus aureus

“…pH is one of the most important parameters to prepare edible films since different pH values tend to solubilize the polymer to form the film-forming solutions [28]. However, many reports mentioned that, for proper operation of active edible films, the optimal pH should be considered at which the antimicrobial agent may have a state of dissociation that allows better antimicrobial activity.…”

Utilization of Edible Films and Coatings as Packaging Materials for Preservation of Cheeses

“…Essential oils and some of its active constituents have been used as antimicrobial and antifungal agents in the preparation of active coatings and films [47][48][49]. In addition to its GRAS grade, essential oils exhibit wide spectrum effects on harmful microorganisms and some has been approved as food additives particularly as flavoring agent [27].…”

Use of herbs, spices and their bioactive compounds in active food packaging

“…In a recent report, authors have not only incorporated aqueous extracts obtained from herbs to polymer matrices but also in the form of volatile essential oils (EOs), normally found in special cells or group of cells present in leaves and stems, and commonly concentrated in leaves, bark or fruits 50 . Some results in the use of EOs extracted from herbs are presented in Table 2.…”

“…They have received attention due to their natural origin and broad antimicrobial and antifungal spectra against different microorganisms, high antioxidant activity and heat stability when incorporated into packaging materials 50,[120][121] . A wide variety of polymers were used to host carvacrol and/or thymol, and different properties in these active materials were evaluated.…”

“…Oregano is a popular culinary herb with high content in EOs containing terpenoids, mainly the monoterpenoid phenols of thymol (5-methyl-2-[1-methylethyl] phenol) and carvacrol (5-isopropyl-2-methyl phenol) 50 . One important feature of the EOs obtained from oregano is their high antimicrobial activity, which is usually determined by the agar plate diffusion method, where the inhibition on solid media was used to determine the antimicrobial effects of active films against different bacteria 26 54,55 .…”