Strategies to improve added value of aromatic and medicinal plants

• Autor(a) principal: Silva, Sofia Jóia
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/12526
• topic: Aloysia Citrodora; Bioplásticos; Cymbopogon Citratus; Daucus Carota; Óleos Essenciais; Domínio/Área Científica::Engenharia e Tecnologia::Bioquímica

Due to the public need to use more natural rather than synthetic products, it is important to look at different essential oils and their possible applications. An example of this search is in the food industry, more specifically, in the packaging area, that where it is important to find active compounds to incorporate into the packages, in order for these to become active and improve the shelf-life time and to provide safer options with less synthetic chemicals in the food conservation. In this way, the aim of this dissertation consisted into characterizing and studying different essential oils (Daucus carota subspecies maritimus, hispidus, maximus, carota e sativus; Aloysia citrodora e Cymbopogon citratus) and their possible applications into chitosan based edible films. In this work the essential oils were previously analyzed by GC-MS, in order to understand their composition. The major compounds found for Daucus carota subsp. maritimus were geranyl acetate, transmethyl-isoeugenol and ?-pinene; geranyl acetate, caryophyllene oxide and transmethyl-isoeugenol for Daucus carota subsp. hispidus; cis-asarone, geranyl acetate and elemicin for Daucus carota subsp. maximus; geranyl acetate, cis-asarone and transmethyl-isoeugenol for Daucus carota subsp. carota and finally carotol e daucol for Daucus carota subsp. sativus; for Aloysia citrodora the major compounds presented were geranial, neral and limonene, and for Cymbopogon citratus geranial, neral e ?myrcene. The Aloysia citrodora and Cymbopogon citratus essential oils were further applied in chitosan films, being tested their functionality by migration assays and their applicability in the conservation of poultry meat. The migration of the active compounds was monitored by migration assays in different food simulant mediums (ethanol 95%, ethanol 50%, ethanol 10% and distilled water), as well as the total phenolic content and antioxidant activity in the simulant medium, throughout the time of ten days. For the Cymbopogon citratus the higher migration occurred at ethanol 50%, on the other hand, for Aloysia citrodora the higher release of phenols occurred with ethanol 95%. When applied to the poultry meat packaging, the meat samples were wrapped in biofilms for 13 days in a refrigerated ambient. Throughout the time, were realizes physical-chemical trials (moisture content, pH, titratable acidity, color, basic volatile nitrogen and thiobatbituric acid reactive substances index) but also the microbial contamination level. Compared to the non-wrapped sample, the packaging allowed an increase to the shelf-life of the meat, since it as shown lower basic volatile nitrogen production, decreased pH level, moisture and lipidic oxidation, as well as lower microbial growth. In comparison with the chitosan control, the incorporation of the essential oils provided a decrease in the lipidic oxidation until the 9th day, without difference between the oils. In terms of antimicrobial activity, the oils did not improve the chitosan activity. As also been verified a yellowish tone to the meat provided by both oils, due to migration. Cymbopogon citratus presented results a little more effective in the oxidation decrease and Aloysia citrodora presented a lower increase of the microbial contamination.