DESCONTAMINAÇAO BIOLÓGICA DE OCRATOXINA A UTILIZANDO UM ENZIMA DE A. NIGER

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Rapid HPLC method for simultaneous detection of aflatoxins and cyclopiazonic from Aspergillus section Flavi

Publication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, Armando

Mycotoxins are secondary metabolites produced by moulds and are an important world-wide food safety concern. Among the most relevant mycotoxigenic producer fungi are some Aspergillus species in particular those belonging to the Aspergillus section Flavi. These are known to produce the highly carcinogenic aflatoxins in agricultural commodities. Due to its impact in animal and human health, these species are among the most intenSively studied ones, being well known producers of aflatoxins (AFB1 , AFB2; AFG1 and AFG2) and cyciopiazonic acid (CPA). Aflatoxins are mainly produced by some strains of Aspergillus flavus and Aspergillus nomius and by most, if not all, strains of Aspergillus parasiticus. On the other hand, cyclopiazonic acid, which naturally occurs in a large variety of crop products as a co-contaminant with aflatoxins, is mainly produced by Aspergillus flavus strains. Together they have been shown to cause health problems in animals and humans, resulting in important economic losses. The production of CPA by Aspergillus section Flavi may also be routinely used for identification purposes since A. parasiticus, A. flavus and A. nomius, exhibit different mycotoxin profiles. The detection and quantification of both these mycotoxins is usually done separately by HPLC with UV detection for CPA and fluorescence detection after post-column derivatization for aflatoxins. There isn't a chromatographic method available to detect simultaneously CPA and the main four aflatoxins.

2010Conference object

Metadata only

HPLC method for simultaneous detection of aflatoxins and cyclopiazonic acid

Publication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, Armando

Aspergillus species in section Flavi are among the most relevant mycotoxigenic fungi. The organisms are well-known producers of the highly carcinogenic aflatoxins and of other mycotoxins, such as cyclopiazonic acid. Aflatoxins and cyclopiazonic acid analyses can be routinely used for identification purposes within the section. Two separate chromatographic runs with distinct columns and detectors for each toxin were required in previous reports. A straightforward high performance liquid chromatography (HPLC) procedure for the simultaneous detection of these compounds in fungal cultures was developed in the present work using a methanol/water mobile phase, post-column photochemical derivatisation and fluorescence detection. The proposed method was tested with standards and fungal extracts of 24 Aspergillus section Flavi strains and compared to the common individual detection of these mycotoxins by HPLC analyses.

2010Journal article

Restricted access

Effect of gamma radiation on mycotoxins solutions

Publication . Calado, Thalita; Antonio, Amilcar L.; Rodrigues, Paula; Cabo Verde, Sandra; Venâncio, Armando

Due to the high toxicity of mycotoxins, many methods have been used to reduce or eliminate them from food and feed. Gamma radiation is one technique that has been investigated with some promising results in degradation of some mycotoxins from food. The aim of this study was to clarify the effect of gamma irradiation on aflatoxin B1 (AFB1) aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2), ochatoxin A (OTA) and zearelone (ZEA). The effect of the presence of moisture during the irradiation process was evaluated. Solutions with the same initial mycotoxin concentration were submitted to gamma radiation doses ranging from 0 to 10.0 kGy, at distinct moisture level – dehydrated, in water, and in methanol:water solution. Mycotoxins levels were determined by high-performance liquid chromatography with fluorescence detection (HPLC-FL), and photochemical post-column derivatization (for aflatoxins). The results showed degradation of mycotoxins with doses above 3.0 kGy, but only when irradiated in aqueous environment. With dehydrated samples, no significant reduction was observed. The results showed that gamma radiation was effective in reducing the mycotoxins concentration, but the presence of water (mainly due to the formation of hydroxyl radicals) had a very significant effect. Acknowledgement: authors acknowledge the financial support of project ChestNutsRad, Programa Operacional do Norte (AdI, Portugal), contract number 13198. Thalita Calado and Luís Abrunhosa received support through grant SFRH/BD/79364/2011 and SFRH/BPD/43922/2008, respectively, from the Fundação para a Ciência e Tecnologia - FCT, Portugal.

2013Conference object

Open access