Action of phenolic extract obtained from rice bran fermented with Rhizopus oryzae in the synthesis of trichothecenes and emerging mycotoxins in sweet corn

Abstract

The phenolic extracts obtained from rice bran cultivated with Rhizopus oryzae were evaluated about their abitily to inhibit the production of trichotecenes and emerging mycotoxins by Fusarium strains on sweet corn cobs (Zea mays L.). The rice bran was cultured with R. oryzae for 48 h at 30 °C. The phenolic compounds were extracted, clarified, lyophilized and ressuspend as water solution with different concentrations. The phenolic acid extracts were applied on sweet corn inoculated by F. cerealis, F. graminearum and F. poae incubated by 15 days at 25 °C and afterward the fermented corn was autoclaved and frozen. The mycotoxins were quantified by LC-MS/MS. The mycotoxin production by all Fusarium strains evaluated was reduced in relation to the control. F. poae was the most sensitive, because its production of the toxins T-2 and HT-2 and BEA was inhibited by phenolic extract 0,5% (p/v), while extract 1% (p/v) inhibited 96% of the DON production. DON, 3ADON and 15ADON production by F. graminearum and F. cerealis was also reduced. Therefore, the extract is a promising antimicotoxinogenic against Fusarium toxins production on sweet corn cobs and should be a good alternative to reuse wastes from agroindustry.

Keywords:
Fusarium; mycotoxins; phenolic compounds; solid state fermentation