Fate of aflatoxins in dry and wet-milled fractions of aspergillus flavus contaminated corn

Abstract

Maize is vulnerable to aflatoxins (AFs) contamination from the field to grain storage. Therefore, it has become a common food safety problem in the food industry. This project investigated the distribution fate of total AFs in dry and wet milled products and coproducts obtained from Aspergillus flavus contaminated maize and the concomitant effects on chemical and functional properties of derived products. White commercial maize was inoculated with A. flavus to produce AFs and then it was processed through milling protocols at laboratory scale. Quantification of AFs was determined by immunoassay and chemical properties (moisture, crude protein, crude fat, minerals) of dry and wet-milled products were determined using standard methods. Results of the dry milling process showed differences in contamination among products being hominy feed the fraction with the highest AFs content (1127.63 ppb per production yield). The main product of this milling process, brewing grits (grits +60), contained approximately 1.05% of the AF present in the whole grain. Protein content increased in grits +35, corn meal and corn flour, whereas the crude fat increased only in grits +20. Wet milling reduced 98% of the total AFs in prime starch. The starch was not significantly affected in terms of pasting properties and macronutrients when compared to the control or uncontaminated maize counterpart. The fiber fractions concentrated the AFs and had lower values of protein. In summary, the dry milling process obtained fractions differing in Afs. Fortunately, the refined brewing grits contained the lowest amounts and contamination did not significantly affected chemical properties. On the other hand, the wet milling process reduce the AFs in the prime starch, but not in fiber fractions. The overall conclusion is that both milling procedures benefited the AFs in the main products, refined grits and prime starch.