Caracterização da contaminação fúngica e por micotoxinas em diferentes fases da cultura do amendoim (Arachis hypogaea L.) produzido no Rio Grande do Sul, Brasil / Characterization of fungi and mycotoxins at different stages of peanut culture (Arachis hypogaea L.) produced in Rio Grande do Sul, Brazil

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2009

RESUMO

Mycotoxins are secondary metabolites produce by filamentous fungi that can contaminate grains in different stages of pre and postharvest management. The objective of this study was to investigate the occurrence of fungi and mycotoxins at different maturation stages of peanut produced in different regions of south of Brazil during 2006/2007 and 2007/2008 harvests. Moreover, to develop an efficient quantification method of aflatoxin B1, based on thin-layer chromatography and charged coupled device detector. Peanut samples, Tatu and Paraguaio varieties, were obtained in regions of Augusto Pestana and Ivorá, in different stages of cultura: (1) soil before planting, (2) pod filling, (3) at harvest, (4) after drying, (5) soil after harvest. The soil contamination was quantified by serial dilution technique and the fungi incidence on grains was determinate by direct planting technique. The toxigenic potential of Aspergillus section Flavi and Aspergillus section Nigri was verified in Coco Medium Ágar and Yeast Extract Sucrose agar medium, respectively. Aflatoxin B1 and ochratoxin A were determinate by on thin-layer chromatography and charged coupled device detector. The predominant species in all samples were Aspergillus flavus and Aspergillus niger var. niger. Among the species of A. flavus and A. parasiticus, 89,3% e 39,2%, produced aflatoxin B1, respectively. None of A. section Nigri isolates were ochratoxin A producers in the conditions tested. Aflatoxin B1 was detected in 50% of samples, with levels of 16.0 ¿g/Kg to 115.0 ¿g/Kg. Ochratoxin A was detected in 25% of samples, with levels of 12.2 ¿g/Kg to 76.9 ¿g/Kg. It was observed the co-occurrence of both mycotoxins in samples of postharvest. The method developed for aflatoxin B1 quantification was sensitive, efficient and practical, with a detection limit of 0.4 ng per spot, a limit of quantification of 1.2 ¿g/kg and average recovery of 92%.

ASSUNTO(S)

micotoxinas aspergillus flavus aspergillus niger contaminação amendoim fungos

ACESSO AO ARTIGO

Documentos Relacionados