This dissertation aims to introduce essential oils as effective antimicrobial substances suitable for food preservation, focusing on the shelf life of meat. Meat is food which is - due to its high nutrient content - susceptible to microbial spoilage. Decaying of meat can be delayed by the selection of appropriate preservation methods. Nowadays there are increasingly used preservative modern methods which differ from classical preservatives procedures mainly in the consideration to the food. As very promising method can be considered preservation by essential oils. In the experimental part of this thesis the effect of encapsulated essential oils into the clay nanoparticles for the shelf life of fresh chicken meat is assessed. For the purpose of the experiment thyme essential oil and oil of savory in two different concentrations (oil:nanoclay - 1:5, 1:10 w/w) were used. Pieces of chicken meat (5 g) were inoculated with Salmonella enteritidis (ATCC 13076) and Escherichia coli (ATCC 25922) and then coated with the clay nanoparticles with the encapsulated essential oils. That treated meat was stored at 4 °C and assessed at 1st, 7th and 14th day of storage, together with three controls. Samples of the chicken meat were explored in terms of microbiological parameters and their inhibitive effect against pathogenic bacteria was examined. Samples were also subjected to sensory analysis, which should provide potential impact of essential oils on the organoleptic characteristics of meat. The results confirmed the antimicrobial activity of both essential oils against pathogenic bacteria. Thyme essential oil, however, showed greater inhibitory activity compared with oil of savory. Thyme essential oil has reduced in both tested bacteria their number in more than 3.5 log CFU.g-1 compared to the controls. Less favorable results were observed in the case of sensory analysis, because in terms of organoleptic characteristics the concentrations of oils were not accepted positively by the assessors. The samples treated with essential oils had undesirable bitter and pungent taste.
This work confirmed the antimicrobial activity of thyme and savory essential oils, which can be used for preservation of fresh meat. But the real application of the essential oils in food may be significantly limited by their impact on the organoleptic characteristics of the product.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:258222 |
| Date | January 2016 |
| Creators | Vojtíšková, Zuzana |
| Contributors | Klouček, Pavel, Fraňková, Adéla |
| Publisher | Česká zemědělská univerzita v Praze |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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