Evaluation of the nixtamalized cornbread-making process as a method of aflatoxin detoxification

Corn is one of the major cereal crops produced worldwide. It has recently been used for the production of healthy, gluten-free, and high-fiber bread. However, corn is highly susceptible to aflatoxin (AF) contamination, representing a serious health concern, as aflatoxins (AFs) are carcinogenic to humans. In this study, the cornbread-making process using the unit operations nixtamalization with different calcium sources, fermentation, and baking was evaluated as a method for AF detoxification at 2 different contamination levels. The nixtamalized cornbread-making process with tequesquite (an alkaline mineral complex) showed an average reduction of 77.12% in AF content from 550.33 µg/kg to 114.50 µg/kg. For the second contamination level (2208.33 µg/kg), the cornbread-making process with the nixtamalization using calcium hydroxide was the most effective, resulting in an average reduction in AF content of 83.58% (362.50 µg/kg). At both levels, the control cornbread samples were significantly different (p < 0.05) from others, reaching an average reduction of 55.43% for level 1 and 58.23% for level 2 (125.73 and 522.33 µg/kg respectively). Additionally, when the AF extracts of cornbread samples were subjected to acidic pH values (pH = 3), an additional reduction in AF content was achieved. The chemical structure of AFs did transform to irreversible forms, with only non-fluorescent derivatives remaining. Our results demonstrate that despite the high contamination of corn used as a raw material, the cornbread-making process including nixtamalization as a unit operation was effective in reducing AF content by more than 80%.