Brazil nuts: Benefits and risks associated with contamination by fungi and mycotoxins

The monotypic type genus Bertholletia produces commercially nutritionally harvested edible seeds, Brazil nuts. It is an important product from the Amazon forest in the food production chain, with a 2008 annual world production of 78,000 tonnes, being Brazil responsible for approximately 40% of it. Although there are beneficial nutritional properties, the prevailing mycobiota of Brazil nuts include fungi that are producers of aflatoxins, such as Aspergillus flavus, A. parasiticus and A. nomius. Aflatoxins have deleterious effects in consumption considering the global distribution chain, affecting major exporting countries. The present review is focused on the importance of Brazil nuts for the Amazon rainforest, emphasizing on the social and environmental impact of its production, on the mycobiota contamination of seeds, and on the presence of mycotoxins and related food safety aspects.     

Chemical,Technological, and Sensory Properties of Wheat Grains (Triticum aestivum L) as Affected by Gaseous Ozonation

Gaseous ozonation, an emerging technology, is applied to microbiological decontamination and to the degradation of residues and contaminants in wheat grains. However, due to its high oxidizing capacity, ozone may cause undesirable effects on the quality of grains or in their derivatives. This study aimed to evaluate the influence of ozone gas on wheat grain quality when exposed to different levels of ozone concentration, exposure time, and grain mass, using a full 2³ factorial design. After the milling of ozonized grains, two fractions were evaluated: flour (A) and bran plus germ (B). In fraction A, the quality of the wheat flour was analyzed by both alveography and farinography. The flour extraction rate, falling number and gluten contents were also measured. The chemical and mineral profiles were determined in both fractions. A sensory evaluation, using the difference-from-control test, was applied to investigate the possible differences in aroma or in overall appearance of the flour obtained from the ozonized grains. The results showed that ozone concentration (60 mg/L) positively affected (p < 0.05) the toughness and the falling number of the flour. The other parameters of alveography, as well as farinography, gluten content, chemical composition, mineral, and sensory profiles were not affected (p > 0.05) by ozonation. This study demonstrated that gaseous ozonation, when applied under the conditions of 10 to 60 mg/L, from 2 to 5 h of exposure, grain mass from 2 to 5 kg, does not cause any negative impact on the wheat quality.     

Predominant mycobiota and aflatoxin content in Brazil nuts

The Brazil nut (Bertholletia excelsa) is an economically important product to the Brazilian Amazon. Currently, its marketing is being affected by the high incidence of aflatoxins (AF) produced by potentially aflatoxigenic fungi associated with its seeds. In this context, the purpose of this study was to determine which part of the nut contributes to contamination by aflatoxins and to identify the mycobiota in Brazil nut samples. Unshelled and shelled nuts were analyzed by measuring the total count of filamentous fungi (Aspergillus sections Flavi, Nigri and Circumdati) in sanitised and non-sanitised treatments. The isolates identified as Aspergillus section Flavi, the major producers of AF, were plated for determination of their aflatoxigenic potential. To perform the AF analysis, samples of Brazil nuts were treated separately. The AF from the shell and kernel were extracted by chloroform and analysed by the HPLC-FD system in isocratic mode. The Aspergillus section Flavi count was 21.67% lower. The production of AF by the isolated fungi was 30% for sanitised and 23.8% for non-sanitised samples. The concentrations obtained of AFB₁ and AFG₁ were higher than those of AFB₂ and AFG₂. The AFB₁ concentrations of shelled nuts and shell samples were 35.0 and 1.78???g/kg, respectively. AFB₂ and AFG₂ were detected only in shelled nut samples. The HPLC-FD analysis presented limits of detection (LOD) and quantification (LOQ) of 0.2 and 0.4???g/kg, respectively.     

Predominant mycobiota and aflatoxin content in Brazil nuts

The Brazil nut (Bertholletia excelsa) is an economically important product to the Brazilian Amazon. Currently, its marketing is being affected by the high incidence of aflatoxins (AF) produced by potentially aflatoxigenic fungi associated with its seeds. In this context, the purpose of this study was to determine which part of the nut contributes to contamination by aflatoxins and to identify the mycobiota in Brazil nut samples. Unshelled and shelled nuts were analyzed by measuring the total count of filamentous fungi (Aspergillus sections Flavi, Nigri and Circumdati) in sanitised and non-sanitised treatments. The isolates identified as Aspergillus section Flavi, the major producers of AF, were plated for determination of their aflatoxigenic potential. To perform the AF analysis, samples of Brazil nuts were treated separately. The AF from the shell and kernel were extracted by chloroform and analysed by the HPLC-FD system in isocratic mode. The Aspergillus section Flavi count was 21.67% lower. The production of AF by the isolated fungi was 30% for sanitised and 23.8% for non-sanitised samples. The concentrations obtained of AFB₁ and AFG₁ were higher than those of AFB₂ and AFG₂. The AFB₁ concentrations of shelled nuts and shell samples were 35.0 and 1.78 μg/kg, respectively. AFB₂ and AFG₂ were detected only in shelled nut samples. The HPLC-FD analysis presented limits of detection (LOD) and quantification (LOQ) of 0.2 and 0.4 μg/kg, respectively.