Biological effects of essential oils - A review

The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

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The Environmental Protection Agency

There is an increased interest in the role that some nutrients may play in preventing or ameliorating the effect of major diseases (for example, some types of cancer, cardiovascular diseases, eye disorders, among others). In this respect, the bioavailability or the proportion of an ingested nutrient that is made available (that is, delivered to the bloodstream) for its intended mode of action is more relevant than the total amount present in the original food. Disruption of the natural matrix or the microstructure created during processing may influence the release, transformation, and subsequent absorption of some nutrients in the digestive tract. Alternatively, extracts of bioactive molecules (for example, nutraceuticals) and beneficial microorganisms may be protected during their transit in the digestive system to the absorption sites by encapsulation in designed matrices. This review summarizes relevant in vivo and in vitro methods used to assess the bioavailability of some nutrients (mostly phytochemicals), types of microstructural changes imparted by processing and during food ingestion that are relevant in matrix-nutrient interactions, and their effect on the bioavailability of selected nutrients.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1750-3841.2007.00274.x

Food microstructure affects the bioavailability of several nutrients.

https://arrow.tudublin.ie/cgi/viewcontent.cgi?article=1009&context=schfsehart

The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients.

The use of 1-methylcyclopropene (1-MCP) on fruits and vegetables.

Postharvest sweet cherry quality and safety maintenance by Aloe vera treatment: A new edible coating

The development and ripening process of sweet cherry (Prunus avium L. cv. 4-70) on the tree was evaluated. For this purpose, 14 different stages were selected in accordance with homogeneous size and color. Some parameters related to fruit quality, such as color, texture, sugars, organic acids, total antioxidant activity, total phenolic compounds, anthocyanins, and ascorbic acid were analyzed. The results revealed that in sweet cherry, the changes in skin color, glucose and fructose accumulation, and softening process are initiated at early developmental stages, coinciding with the fast increase in fruit size. Also, the decrease in color parameter a was correlated with the greatest accumulation of total anthocyanins. Ascorbic acid, total antioxidant activity (TAA), and total phenolic compounds decreased during the early stages of sweet cherry development but exponentially increased from stage 8, which coincided with the anthocyanin accumulation and fruit darkening. TAA showed positive correlations (r(2) = 0.99) with both ascorbic acid and total phenolic compounds and also with the anthocyanin concentration from stage 8. Taking into account the reduced shelf life of sweet cherry and to ensure that these fruits reach consumers with the maximum organoleptic, nutritional, and functional properties, it is advisable to harvest sweet cherries at stage 12 of ripening.

Chemical constituents and antioxidant activity of sweet cherry at different ripening stages.

Sweet cherry shows severe problems for commercialisation mainly due to incidence of decay and a fast loss of sensory quality, both for fruit and stem. A package has been developed based on the addition of eugenol, thymol, menthol or eucalyptol (pure essential oils) separately to trays sealed with polypropylene bags to generate a modified atmosphere (MAP). In addition, cherries in MAP (without essential oils) were selected and served as controls. All cherries were stored during 16 days at 1 °C and 90% RH. Steady-state atmosphere was reached after 9 days of cold storage with 2–3% of CO2 and 11–12% of O2 with no significant differences between treated and control, with the exception of eucalyptol, in which significant increases in CO2 and decreases of O2 were obtained. When fruit quality parameters were determined, those treated with eugenol, thymol or menthol showed benefits in terms of reduced weight loss, delayed colour changes and maintenance of fruit firmness compared with control. Stem remained green in treated cherries while they became brown in control. However, cherries packaged with eucalyptol behaved even worst than control cherries, with generation of off-flavours, loss of quality and stem browning. Finally, the microbial analysis showed that all essential oils reduced moulds and yeasts and total aerobic mesophilic colonies by 4- and 2-log CFU compared with control, respectively. In conclusion, the use of MAP in combination with eugenol, thymol or menthol is an effective tool on maintaining cherry fruit quality and reducing the occurrence of decay. Industrial relevance The data presented in this work suggest that the use of pure essential oils (eugenol, thymol or menthol) in combination with modified atmosphere packaging (MAP) is an innovative and useful tool as alternative to the use of synthetic fungicides in fruits and vegetables, especially for those which are highly perishable and have a short shelf-life, as cherries. These compounds have been included in the list of generally recognized as safe (GRAS) compounds by FDA. As far as we know, this is the first paper dealing on the use of natural antifungal compounds and MAP and that these combined technologies confer benefits in fruit storage and retailing, with reduction in spoilage microorganisms, maintenance of cherry quality attributes and extension of shelf-life. The effects of these natural compounds on individual microorganisms, both responsible for spoilage and food-borne pathogens, as well as the minimum concentration to gain effectiveness deserve further research.

The use of natural antifungal compounds improves the beneficial effect of MAP in sweet cherry storage

A novel edible coating based on Aloe vera gel obtained according to SP Patent Filed 200302937 has been used as a means of preservation to maintain the quality and safety of cv. Crimson Seedless table grapes during cold storage and subsequent shelf life. Table grapes have a crucial economic value as a dessert fruit, but once harvested show a reduction of shelf life due to a rapid loss of quality. Uncoated clusters showed a rapid deterioration with an estimated shelf life period of 7 days at 1 degrees C plus 4 days at 20 degrees C, based on the fast weight loss, color changes, accelerated softening and ripening, rachis browning, and high incidence of berry decay. On the contrary, those clusters treated with A. vera gel significantly delayed the above parameters related to postharvest quality losses, and storability could be extended up to 35 days at 1 degrees C. Interestingly, this edible coating was able to reduce the initial microbial counts for both mesophillic aerobic and yeast and molds, which significantly increased in uncoated berries over storage. Moreover, the sensory analyses revealed beneficial effects in terms of delaying rachis browning and dehydration and maintenance of the visual aspect of the berry without any detrimental effect on taste, aroma, or flavors. To the authors' knowledge, this is the first time A. vera gel has been used as an edible coating in fruits, which would be an innovative and interesting means for commercial application and an alternative to the use of postharvest chemical treatments.

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Fabián Guillén

Papers

Postharvest sweet cherry quality and safety maintenance by Aloe vera treatment: A new edible coating

Chemical constituents and antioxidant activity of sweet cherry at different ripening stages.

The use of natural antifungal compounds improves the beneficial effect of MAP in sweet cherry storage

Novel edible coating based on aloe vera gel to maintain table grape quality and safety.

The combination of modified atmosphere packaging with eugenol or thymol to maintain quality, safety and functional properties of table grapes