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The stability of deoxynivalenol (DON) and deoxynivalenol-3-glucoside (DON-3-glucoside) during the breadmaking process was studied. Some enzymes used in the bakery industry were examined to evaluate their effects on DON and DON-3-glucoside. The level of DON in breads without added enzymes was reduced (17-21%). Similarly, the addition of cellulase, protease, lipase and glucose-oxidase did not modify this decreasing trend. The effect of xylanase and alpha-amylase on DON content depended on the fermentation temperature. These enzymes reduced the DON content by 10-14% at 45 degrees C. In contrast, at 30 degrees C, these enzymes increased the DON content by 13-23%. DON-3-glucoside levels decreased at the end of fermentation, with a final reduction of 19-48% when no enzymes were used. However, the presence of xylanase, alpha-amylase, cellulase and lipase resulted in bread with greater quantities of DON-3-glucoside when fermentation occurred at 30 degrees C. The results showed that wheat bran and flour may contain hidden DON that may be enzymatically released during the breadmaking process when the fermentation temperature is close to 30 degrees C. The authors are grateful to the Spanish government (project AGL2014-55379-P) for financial support. A. Vidal thanks the Spanish government (Ministry of Education) for the pre-doctoral grant.

Aflatoxins are the most potent genotoxic and carcinogenic mycotoxins. To date, research has only focused on the presence of free aflatoxins in agricultural commodities. Therefore, the main objective of this study was to investigate the occurrence of possible modified aflatoxins in maize. Different hydrolysis methods were applied to convert modified mycotoxins into their free aflatoxins. Eighteen aflatoxin-contaminated maize samples were incubated with potassium hydroxide, trifluoromethanesulfonic acid and several enzymes to induce hydrolysis. Potassium hydroxide caused a total reduction of aflatoxins, while trifluoromethanesulfonic acid did not lead to an increase in free aflatoxins, neither did treatment with a protease. However, α-amylase and cellulase incubation caused significant increases in the total free aflatoxin content, 15 ± 8% and 13 ± 5%, respectively. These results show that a small proportion of aflatoxins could be associated to matrix substances in plants. Consequently, hydrolysis could occur during food processing and during mammalian digestion, leading to an underestimation of the total aflatoxin content. The authors acknowledge the Spanish government (project AGL2014-55379-P) for the financial support. A. Vidal acknowledges the Spanish government (Ministry of Education) for the pre-doctoral grant. The authors are grateful to Mrs. Cynthia Chilaka for the kind provision of the maize samples.