Café - estudo da biodiversidade microbiana de frutos de café do Brasil e seleção de cepas de leveduras e bactérias lácticas com ação fungistática contra Aspergillus ochraceus produtor de ocratoxina A
Data
2004
Autores
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Universidade Federal do Paraná
Resumo
Avaliou-se a ação fungistática de leveduras e bactérias lácticas, isoladas de cerejas de café provenientes de várias regiões do Brasil, contra Aspergillus ochraceus produtor de ocratoxina A. Quando testadas em placas de ágar, vinte e três, das trinta e cinco cepas de leveduras e seis das vinte cepas de bactérias lácticas revelaram diferentes graus de inibição do micélio. Dessas Candida lambica 13b e Lactobacillus brevis LPB03, apresentaram maior potencial antagônico. Inoculada em cultura submersa, Candida lambica 13b reduziu em 95,87% a biomassa fúngica. Inoculada em grãos de café verde artificialmente contaminados com esporos de Aspergillus ochraceus, reduziu em 88,37% a formação de ocratoxina A, quantificada por cromatografia líquida de alta eficiência com fluorescência. A caracterização dos metabólitos por cromatografia gasosa acoplada a espectrometria de massas revelou a formação de dois compostos, um alcoólico (composto 1): 2-2 ditiobis-etanol(CAS No 1892-29-1) ou álcool p-(tio metil) benzil (CAS No 3446-90-0) e um fenólico (composto 2): 2-(1-etilfenil)-fenol (CAS No 4237- 44-9) ou fenoxietil-benzeno(CAS No 54852-74-3) possíveis responsáveis pelo caráter fungistático, comprovando que utilização de espécies antagônicas pode manter a sanidade de grãos de café, evitando restrições no seu consumo ou comercialização.
The fungistatic action of yeasts and lactic acid bacteria strains, isolated from coffee cherries of several regions of Brazil against Aspergillus ochraceus producer of ochratoxin A was evaluated. When tested in agar plates, twenty three of the thirty five isolated yeasts strains and six of lactic bacteria of the twenty isolated revealed different levels of mycelium inhibition. Of those Candida lambica 13b and Lactobacillus brevis LPB 03 showed greater antagonistic potential. Inoculated in submerse culture, Candida lambica reduced by 95.87% the fungal biomass. Inoculated in green coffee cherries artificially contaminated with Aspergillus ochraceus spores, it reduced 88.37% the ochratoxin A synthesis, which was quantified by high performance liquid chromatography with fluorescence. The characterization of the metabolites by gas chromatography coupled to mass spectrometry revealed the formation of two compounds, an alcoholic (compound 1): Ethanol, 2,2’-dithiobis-(CAS No 1892-29-1) or p-(Methylthio)benzyl alcohol (CAS No 3446-90-0) and a phenolic (compound 2): Phenol, 2-(1-phenylethyl)- (CAS No 4237-44-9) or Benzene, ethylphenoxy-(CAS No 54852-74-3), possibly the responsibles for the fungistatic character, proving that the utilization of antagonistic species can maintain the quality of coffee grains, avoiding restrictions in its consumption or commercialization.
The fungistatic action of yeasts and lactic acid bacteria strains, isolated from coffee cherries of several regions of Brazil against Aspergillus ochraceus producer of ochratoxin A was evaluated. When tested in agar plates, twenty three of the thirty five isolated yeasts strains and six of lactic bacteria of the twenty isolated revealed different levels of mycelium inhibition. Of those Candida lambica 13b and Lactobacillus brevis LPB 03 showed greater antagonistic potential. Inoculated in submerse culture, Candida lambica reduced by 95.87% the fungal biomass. Inoculated in green coffee cherries artificially contaminated with Aspergillus ochraceus spores, it reduced 88.37% the ochratoxin A synthesis, which was quantified by high performance liquid chromatography with fluorescence. The characterization of the metabolites by gas chromatography coupled to mass spectrometry revealed the formation of two compounds, an alcoholic (compound 1): Ethanol, 2,2’-dithiobis-(CAS No 1892-29-1) or p-(Methylthio)benzyl alcohol (CAS No 3446-90-0) and a phenolic (compound 2): Phenol, 2-(1-phenylethyl)- (CAS No 4237-44-9) or Benzene, ethylphenoxy-(CAS No 54852-74-3), possibly the responsibles for the fungistatic character, proving that the utilization of antagonistic species can maintain the quality of coffee grains, avoiding restrictions in its consumption or commercialization.
Descrição
Tese de Doutorado defendida na Universidade Federal do Paraná.
Palavras-chave
Aspergillus ochraceus, Candida lambica, Lactobacillus brevis, Ação fungistática, Ocratoxina A
Citação
BEUX, M. R. Café - estudo da biodiversidade microbiana de frutos de café do Brasil e seleção de cepas de leveduras e bactérias lácticas com ação fungistática contra Aspergillus ochraceus produtor de ocratoxina A . 2004. 144 f. Tese (Doutorado em Tecnologia de Alimentos) - Universidade Federal do Paraná, Curitiba. 2004.