The paper “Essential oils: Sources of antimicrobials and food preservatives” by Pandey et al. discusses and summarizes the scientific findings regarding essential oils used in the food industry as preservatives. Specifically, the authors concentrate on the qualities of essential oils to serve as antibacterial, bactericidal, antifungal, and fungicidal food preservatives. They claim that more research into this topic is needed as natural extracts are safe, eco-friendly, and cost-effective and, thus, are potentially good to substitute for synthetic oils, which are found to have adverse health effects. Therefore, this paper intends to summarize the main findings of the article under review.
In the beginning, the authors discuss the functions of essential oils’ active components that can be relevant for food preservation purposes. For instance, terpenoids that aromatic and medical plants produce are found to have a crucial role in protecting biological organisms from pathogens. Additionally, monoterpenes that exist in essential oils can deter microorganisms from reproduction and development and, thus, are “antimicrobial in nature.” In a similar vein, such plants as Nigella sativa and Cymbopogon citratus can produce bacillus subtilis which is an effective fungicide. Therefore, it is maintained that essential oils consist of components that are able to fight against bacterial and fungi pathogens successfully.
Regarding antibacterial attributes, the authors found that generally, essential oils have less effect on Gram-negative bacteria than on Gram-positive bacteria. That is explained by the fact that the presence of hydrophilic lipopolysaccharides in the former bacteria’s outer membrane can eliminate the antibacterial effect of active components found in natural plant extractions. However, although the antibacterial qualities of essential oils are relatively well-known, it is maintained that there is a lack of evidence that they are effective against yeasts and molds.
Essential oils are also found to have good antifungal potential as they are able to disintegrate fungal hyphae due to the existing mono- and sesquiterpene compounds. Additionally, active components that are present in natural extracts can lead to fungi membrane swelling and, as a result, reduce its functioning. Furthermore, the lipophilicity of essential oils allows them to penetrate cell walls and significantly reduce cell-wall synthesis by enzymes which negatively affects fungi reproduction and functioning. Therefore, it can be concluded that essential oils can effectively fight the fungi spore spread and increase the preservation time of the food.