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Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2020.tde-21052020-123021
Document
Author
Full name
Juliana Scabello Prando Zambianco
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 2020
Supervisor
Committee
Vieira, Thais Maria Ferreira de Souza (President)
Alvim, Izabela Dutra
Gloria, Eduardo Micotti da
Oliveira, Jacqueline de
Title in Portuguese
Microencapsulação do óleo essencial de alecrim pimenta (Lippia sidoides): atividade antifúngica in vitro e sua influência sobre a vida útil de fatias de pão sem glúten
Keywords in Portuguese
Aspergillus niger
Lippia sidoides
Conservantes naturais
Exposição aos voláteis
Spray drying
Abstract in Portuguese
A demanda por alimentos naturais tem despertado o interesse por parte das indústrias em repensar formulações de alimentos já existentes no mercado. Na indústria de panificação, os maiores desafios são a deterioração por bolores e a busca por alternativas naturais ao uso de conservantes sintéticos. Estudos recentes têm demonstrado resultados positivos com a utilização de óleos essenciais na ação antifúngica de espécies deteriorantes em pães. Nota-se ainda que a utilização de óleos essenciais encapsulados e por difusão dos voláteis nas embalagens pode ser uma interessante saída para a conservação dos compostos bioativos presentes nos óleos, minimizando sua influência nas propriedades organolépticas de pães. O objetivo do presente estudo foi avaliar o potencial antifúngico do óleo essencial de alecrim pimenta (Lippia sidoides) microencapsulado e sua influência sobre a vida útil de pães, através da liberação de seus compostos voláteis dentro das embalagens. O processo de microencapsulação por spray drying ocorreu utilizando-se diferentes materiais de parede (goma arábica e maltodextrina:amido modificado) e posteriormente obteve-se a caracterização das micropartículas. Ainda, a composição química do óleo essencial livre e do recuperado das micropartículas foi obtida por cromatografia gasosa (CG/MS e CG/FID). Foram realizados testes in vitro por diluição em ágar e exposição aos voláteis do óleo essencial e encapsulado, de modo a determinar a concentração inibitória mínima (CIM) frente à espécie A. niger, previamente isolada e identificada. A ocorrência de crescimento fúngico em fatias de pão, expostas aos voláteis do óleo essencial e das micropartículas, também foi verificada. Ao final, uma análise sensorial dos pães foi realizada, a fim de verificar a influência dos compostos bioativos sobre as propriedades organolépticas dos pães avaliados. A atividade antifúngica in vitro avaliada por diluição em ágar mostrou que o óleo essencial apresentou resultados inferiores à exposição aos voláteis, o que é supostamente explicado pela baixa diluição do óleo no meio de cultura. Em contrapartida, no método de exposição aos voláteis as micropartículas do óleo essencial de L. sidoides apresentaram efeito inibitório in vitro superior ao encontrado no óleo essencial livre. Não houve efeito significativo do material de parede sobre a composição química do óleo essencial. Quando aplicadas nas embalagens de pão, as micropartículas apresentaram efeito inibitório inferior ao óleo essencial livre. No entanto, as micropartículas apresentaram menor impacto sensorial quando comparado ao óleo livre, indicando que a estratégia de encapsulação pode ser promissora. Com estudos futuros de otimização do material encapsulado quanto à formulação (quantidade de óleo, material de parede, estudo de liberação dos compostos na embalagem) pode-se obter um material eficiente na preservação do produto.
Title in English
Microencapsulation of rosemary pepper (Lippia sidoides) essential oil: in vitro antifungal activity and its influence on the shelf life of gluten-free bread slices
Keywords in English
Aspergillus niger
Lippia sidoides
Natural preservatives
Spray drying
Volatile exposure
Abstract in English
The demand for natural and sustainable foods has sparked the interest on the part of the industries in rethinking food formulations already existing in the market. In the bakery industry, one of the current challenges is directly related to the mold deterioration. In view of these reports, the current challenge for the bakery industry is to find ways to replace synthetic preservatives with natural conservation alternatives. Recent studies have shown positive results with the use of essential oils in the antifungal activity against deteriorating species in breads. It is also noted that the use of encapsulated essential oils and by diffusion of volatile compounds in packaging can be an interesting way to preserve the bioactive compounds present in the oils and also to minimize their interference in the organoleptic properties of breads. The present study has as main objective to evaluate the antifungal potential of the microencapsulated Lippia sidoides essential oil and its influence on the shelf life of breads, through the release of its volatile compounds inside the packages. The microencapsulation process by spray drying took place using different wall materials (gum arabic and maltodextrin: modified starch), and subsequently the characterization of the microparticles was obtained. Also, the chemical composition of the free essential oil and the oil recovered from the microparticles was obtained by gas chromatography (CG / MS and CG / FID). In vitro tests were performed by agar dilution and exposure to volatiles of the essential oil and its microparticles, in order to determine the minimum inhibitory concentration (MIC) against the species A. niger, previously isolated and identified. The occurrence of fungal growth in slices of bread, exposed to the volatiles of essential oil and microparticles, was also verified. At the end, a sensory analysis of the bread was performed in order to verify the influence of bioactive compounds on the organoleptic properties of the breads evaluated. The in vitro antifungal activity evaluated by agar dilution showed that the essential oil presented lower results than those observed for volatile exposure, which is supposedly explained by the low dilution of the oil in the culture medium. On the other hand, in the method of exposure to volatiles, the microparticles had an inhibitory effect in vitro superior to that found in the free essential oil. There was no significant difference between the chemical composition of the evaluated wall materials, and both had a similar composition compared to the free essential oil. When applied to bread packaging, microparticles showed only a slight inhibitory effect, while treatment with free essential oil showed greater antifungal activity. Despite the lower performance of microencapsulated oil in growth inhibition, it had less sensory impact on bread when compared to free oil, indicating that the encapsulation strategy can be promising for bread preservation. With further studies of optimization of the encapsulated material in terms of formulation (quantity of oil, wall material, study of the release of the compounds in the packaging), an efficient material for the preservation of the product can be obtained.
 
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Publishing Date
2020-05-22
 
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