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Pesquisa da atividade antifúngica com bactérias do ácido láctico
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| Resumo, Índice, Introdução | 334.11 KB | Adobe PDF | ||
| Documento Principal | 1.22 MB | Adobe PDF |
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Advisor(s)
Abstract(s)
Apesar dos avanços tecnológicos, a deterioração fúngica é ainda uma questão importante na indústria de laticínios. Um dos métodos de prevenção tradicionais inclui as tecnologias barreira, tais como conservantes químicos. Atualmente, existe uma procura por novas técnicas de conservação para atender à crescente procura dos consumidores por produtos lácteos menos processados e sem conservantes. Essas novas técnicas incluem a biopreservação usando culturas antifúngicas protetoras. Desta forma, o presente estudo tem como objetivo pesquisar bactérias do ácido láctico (BAL) isoladas de queijo de S. Jorge com propriedades antifúngicas, e com potencialidade de aplicação em queijos curados. Foram avaliados 108 isolados pela sua capacidade de inibir o crescimento de duas espécies de fungos dos filos Ascomycota e Zygomycota, Aspergillus caesiellus (ATCC 42693) e Mucor racemosus (ATCC 42647). Para deteção da atividade antifúngica foi utilizado o método de difusão em agar. Observou-se uma inibição média/elevada do crescimento de Mucor racemosus por isolados pertencentes às espécies Enterococcus faecalis, Enterococcus gilvus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus curvatus e Leuconostoc mesenteroides subsp.
dextranicum. O fungo A. caesiellus foi mais sensível à atividade antimicrobiana das BAL em comparação com o M. racemosus. Foram selecionados 6 isolados que apresentaram maior inibição do crescimento do M. racemosus (com os códigos SJ22, SJ46, SJ53. SJ83, SJ87 e SJ88) para avaliação dos compostos produzidos por estas BAL em meio de cultura (extratos). Os extratos filtrados produzidos pelos isolados SJ53, SJ87 e SJ88, identificados como Lactobacillus curvatus, Lactobacillus casei e Lactobacillus paracasei, apresentaram taxas de inibição superiores a 90%. Para os extratos neutralizados, destacou-se o isolado SJ88 (Lactobacillus paracasei), que apresentou uma taxa de inibição de 73%, significativamente superior (P<0,05) aos restantes isolados. O presente trabalho demonstrou assim o potencial de alguns isolados, pertencentes ao género Lactobacillus, para inibir o crescimento de fungos. Devido ao estatuto GRAS destas espécies, elas apresentam um forte potencial para serem utilizadas na proteção dos produtos lácteos contra o crescimento de fungos indesejáveis.
ABSTRACT: Despite technological advances, fungal spoilage is still a main issue in the dairy industry. Among the present methods in use, a large focus concerns the replacement of traditional hurdle technologies such as chemical preservatives by new techniques to meet the increasing consumer demand for less-heavily processed and preservative-free dairy products. These new techniques include biopreservation using antifungal bioprotective cultures. Thus, the present study aims to evaluate lactic acid bacteria (LAB) isolated from São Jorge cheese with antifungal properties, and with potential application in ripened cheeses. One hundred and seven isolates were evaluated by ability of inhibit the growth of two species of fungi in the phyla Ascomycota and Zygomycota, Aspergillus caesiellus (ATCC 42693) and Mucor racemosus (ATCC 42647). The antifungal activity was evaluated by the agar-diffusion assay. A medium/high inhibition of growth of Mucor racemosus was produced by isolates belonging to the species Enterococcus faecalis, Enterococcus gilvus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus curvatus and Leuconostoc mesenteroides subsp. dextranicum. The fungus Aspergillus caesiellus was more sensitive to antimicrobial activity of BAL compared to Mucor racemosus. The Six isolates that showed greater inhibition of Mucor racemosus growth were selected (codes SJ22, SJ46, SJ53. SJ83, SJ87 and SJ88) for evaluation of the compounds produced by these BAL in culture medium (cell-free supernatant). The pure supernatants produced by isolates SJ53, SJ87 and SJ88, identified as Lactobacillus curvatus, Lactobacillus casei and Lactobacillus paracasei, showed inhibition rates over 90%. For supernatants neutralized, the isolate SJ88 (Lactobacillus paracasei), presented a 73% inhibition rate, significantly higher (P < 0.05) than the remaining isolates. The present study demonstrated the high potential of some isolates, belonging to the genus Lactobacillus, to inhibit the growth of fungi. Due to the GRAS status of these species, they offer great potential in the protection against mold growth in dairy products.
ABSTRACT: Despite technological advances, fungal spoilage is still a main issue in the dairy industry. Among the present methods in use, a large focus concerns the replacement of traditional hurdle technologies such as chemical preservatives by new techniques to meet the increasing consumer demand for less-heavily processed and preservative-free dairy products. These new techniques include biopreservation using antifungal bioprotective cultures. Thus, the present study aims to evaluate lactic acid bacteria (LAB) isolated from São Jorge cheese with antifungal properties, and with potential application in ripened cheeses. One hundred and seven isolates were evaluated by ability of inhibit the growth of two species of fungi in the phyla Ascomycota and Zygomycota, Aspergillus caesiellus (ATCC 42693) and Mucor racemosus (ATCC 42647). The antifungal activity was evaluated by the agar-diffusion assay. A medium/high inhibition of growth of Mucor racemosus was produced by isolates belonging to the species Enterococcus faecalis, Enterococcus gilvus, Lactobacillus paracasei, Lactobacillus casei, Lactobacillus curvatus and Leuconostoc mesenteroides subsp. dextranicum. The fungus Aspergillus caesiellus was more sensitive to antimicrobial activity of BAL compared to Mucor racemosus. The Six isolates that showed greater inhibition of Mucor racemosus growth were selected (codes SJ22, SJ46, SJ53. SJ83, SJ87 and SJ88) for evaluation of the compounds produced by these BAL in culture medium (cell-free supernatant). The pure supernatants produced by isolates SJ53, SJ87 and SJ88, identified as Lactobacillus curvatus, Lactobacillus casei and Lactobacillus paracasei, showed inhibition rates over 90%. For supernatants neutralized, the isolate SJ88 (Lactobacillus paracasei), presented a 73% inhibition rate, significantly higher (P < 0.05) than the remaining isolates. The present study demonstrated the high potential of some isolates, belonging to the genus Lactobacillus, to inhibit the growth of fungi. Due to the GRAS status of these species, they offer great potential in the protection against mold growth in dairy products.
Description
Dissertação de Mestrado, Tecnologia e Segurança Social, 14 de maio de 2019, Universidade dos Açores.
Keywords
Acido Láctico Bactérias Lácticas Microbiologia Alimentar Queijo de São Jorge Lactic Bacteria
Pedagogical Context
Citation
Moreno, Natanael Pereira. "Pesquisa da atividade antifúngica com bactérias do ácido láctico". 2019. 61 p.. (Dissertação de Mestrado em Tecnologia e Segurança Social). Angra do Heroísmo: Universidade dos Açores, 2018. [Consult. Dia Mês Ano]. Disponível em www:<http://hdl.handle.net/10400.3/5423>.