Fate of aflatoxins from a novel procedure for tortilla making based on infrared heating

Abstract

The fate of aflatoxins was studied during nixtamalization by using two tortilla making processes. Maize contaminated with two aflatoxin contents (AC) [AC1=173 ng g-1 and AC2=370 ng g-1] was processed by the traditional (TNP) as well as an innovative nixtamalization procedure based on infrared heating (IRNP). In the case of tortillas from TNP, the aflatoxin contents were 17 ng g-1 and 61 ng g-1, achieved higher degradation rates of 90% and 84%, corresponding to AC1 and AC2, respectively. In contrast, in tortillas obtained from IRNP, the aflatoxin contents were 50 ng g-1 and 100 ng g-1, with degradation rates of 71% and 73%, respectively. Acidification of extracts prior to mycotoxin quantification did not result in a rebuilding of the aflatoxin structure; on the contrary, an extra reduction in the aflatoxin content was observed, up to 15% and up to 25% in tortillas produced with TNP and IRNP, respectively. A quadratic function and a linear function were fitted to evaluate the aflatoxin content in tortillas; these mathematical functions indicated that the initial aflatoxin content in the maize used to produce tortillas within the maximum limit allowed in Mexico are 163 ng g-1 for TNP and 44 ng g-1 for IRNP, respectively. Based on these results, IRNP seems to be safe and effective for aflatoxin reduction during tortilla manufacture.