Abstract

The application of natural antifungal substances is motivated by the need for alternatives to existing methods that are not always applicable, efficient, or that do not pose risk to consumers or the environment. Furthermore, studies on the behaviour of toxigenic species in the presence of natural fungicides have enabled their safe application in the food chain. This study aimed to identify the fraction of the rice grain with greater inhibitory activity of amylase and related to its antifungal and antimycotoxigenic potential against Fusarium graminearum CQ 244 biomass. The greatest inhibitory effect was observed in extracts of bran, which inhibited by 90% the fungal amylase activity. The primary fractionation of the rice bran extract was more efficient when ethanolic extracts was precipitated by acetone, resulting in a specific inhibition estimated at 20 μg_{hydrolysed starch} min^-1mg protein¹, PF 45 and recovery 61%. The rice bran protein extracts showed fungistatic activity against F. graminearum, with MIC₅₀ of 419 μg ml^-1 and 168 mg ml^-1 estimated from glucosamine and amylase inhibition, respectively, which cause 63% biomass inhibition and 40% of the nivalenol (NIV) production.

Key words: Rice, Fusarium graminearum, glucosamine, amylase, nivalenol (NIV).

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