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Item Ochratoxigenic fungi associated with green coffee beans (Coffea arabica L.) in conventional and organic cultivation in Brazil(Sociedade Brasileira de Microbiologia, 2013-10-09) Rezende, Elisângela de Fátima; Borges, Josiane Gonçalves; Cirillo, Marcelo Ângelo; Prado, Guilherme; Paiva, Leandro Carlos; Batista, Luís RobertoThe genera Aspergillus comprises species that produce mycotoxins such as aflatoxins, ochratoxins and patulin. These are cosmopolitan species, natural contaminants of agricultural products. In coffee grains, the most important Aspergillus species in terms of the risk of presenting mycotoxins belong to the genera Aspergillus Section Circumdati and Section Nigri. The purpose of this study was to assess the occurrence of isolated ochratoxigenic fungi of coffee grains from organic and conventional cultivation from the South of Minas Gerais, Brazil, as well as to evaluate which farming system presents higher contamination risk by ochratoxin A (OTA) produced by fungi. Thirty samples of coffee grains (Coffea arabica L.) were analysed, being 20 of them of conventional coffee grains and 10 of them organic. The microbiological analysis was done with the Direct Plating Technique in a Dichloran Rose Bengal Chloramphenicol Agar (DRBC) media. The identification was done based on the macro and micro morphological characteristics and on the toxigenic potential with the Plug Agar technique. From the 30 samples analysed, 480 filamentous fungi of the genera Aspergillus of the Circumdati and Nigri Sections were isolated. The ochratoxigenic species identified were: Aspergillus auricoumus, A. ochraceus, A. ostianus, A. niger and A. niger Aggregate. The most frequent species which produces ochratoxin A among the isolated ones was A. ochraceus, corresponding to 89.55%. There was no significant difference regarding the presence of ochratoxigenic A. ochreceus between the conventional and organic cultivation systems, which suggests that the contamination risk is similar for both cultivation systems.Item Enzymatic and toxigenic potential of fungi isolated from coffee beans(Editora UFLA, 2013-01) Rezende, Elisângela de Fátima; Couto, Fabiana Aparecida; Borges, Josiane Gonçalves; Silva, Daiani Maria da; Batista, Luis RobertoThe presence of some species of filamentous fungi in coffee beans may indicate reduced quality and risks of mycotoxins. Moreover, other species may be bioprotective of the bean integrity, indicators of environmental changes and informative. The objective of this study was to evaluate the enzymatic activity and toxigenic potential of filamentous fungi isolated from 12 samples of coffee beans (11 samples of Coffea arabica and 1 sample of Coffea canephora). 182 fungi were isolated and identified belonging to two genera: Aspergillus and Penicillium. Of the 138 fungi from the genus Aspergillus belonging to the Section Nigri and Section Circumdati tested, 28.3 % were producers of ochratoxin A, particularly for the species A. ochraceus and A. ostianus. Of the 14 isolates of Aspergillus flavus tested, 78.6 % were producers of aflatoxin B1 and B2 . Aspergillus versicolor , Cladosporium cladosporioides , Penicillium roqueforti and Penicillium sp . showed an enzymatic index greater than 2 (IE> 2) for polygalacturonase and Penicillium funiculosum , Penicillium and Aspergillus sclerotiorum aurantiogriseum showed pectate lyase activity above 2 ( IE> 2). Species of Penicillium brevicompactum showed potential pectinolitica for the two enzymes tested. These results demonstrate that coffee beans can be an important source of fungi with biotechnological potential and potentially toxigenic fungi have limited enzyme capacity of degrading pectin -rich substrates such as mucilage and produce mycotoxins.Item Potencial enzimático e toxigênico de fungos isolados de grãos de café(Editora UFLA, 2013-01) Rezende, Elisângela de Fátima; Couto, Fabiana Aparecida; Borges, Josiane Gonçalves; Silva, Daiani Maria da; Batista, Luis RobertoA presença de algumas espécies de fungos filamentosos em grãos de café pode indicar redução da qualidade e riscos de micotoxinas. Por outro lado, outras espécies podem ser bioprotetoras da integridade dos grãos, indicadores de alterações ambientais e indicativo. Objetivou-se, neste estudo, avaliar a atividade enzimática e o potencial toxigênico de fungos filamentosos isolados de 12 amostras de grãos de café (11 amostras de Coffea arabica e uma amostra de Coffea canephora). Foram isolados e identificados 182 fungos pertencentes a dois gêneros: Aspergillus e Penicillium. Dos 138 fungos do gênero Aspergillus pertencentes à Seção Circumdati e Seção Nigri testados, 28,3% foram produtores de ocratoxina A, com destaque para as espécies A. ochraceus e A. ostianus. Dos 14 isolados de A. flavus testados, 78,6% foram produtores de aflatoxina B1 e B2. A. versicolor, Cladosporium cladosporioides, P. roqueforti e Penicillium sp. apresentaram índice enzimático superior a 2 (IE > 2) para poligalacturonase e P. funiculosum, P. aurantiogriseum e Aspergillus sclerotiorum apresentaram atividade pectato liase acima de 2 (IE > 2). Os isolados de P. brevicompactum apresentaram potencial pectinolítico para as duas enzimas testadas. Esses resultados demonstram que os grãos de café podem ser importante fonte de fungos com potencial biotecnológico e que os fungos potencialmente toxigênicos apresentam limitada capacidade enzimática de degradar substratos ricos em pectina como a mucilagem e produzir micotoxinas.