Comparison of nixtamalization and extrusion processes for a reduction in aflatoxin content

Abstract

Traditional nixtamalization and an extrusion method for making the dough (masa) for corn tortillas that requires using lime and hydrogen peroxide were evaluated for the detoxification of aflatoxins. The traditional nixtamalization process reduced levels of aflatoxin B1 (AFB1) by 94%, aflatoxin M1 (AFM1) by 90% and aflatoxin B1 -8,9-dihydrodiol (AFB1 -dihydrodiol) by 93%. The extrusion process reduced levels of AFB1 by 46%, AFM1 by 20% and AFB1 -dihydrodiol by 53%. Extrusion treatments with 0, 0.3 and 0.5% lime reduced AFB1 levels by 46, 74 and 85%, respectively. The inactivation of AFB1, AFM1 and AFB1 -dihydrodiol in the extrusion process using lime together with hydrogen peroxide showed higher elimination of AFB1 than treatments with lime or hydrogen peroxide alone. The extrusion process with 0.3% lime and1.5% hydrogen peroxide was the most effective process to detoxify aflatoxins in corn tortillas, but a high level of those reagents negatively affected the taste and aroma of the corn tortilla as compared with tortillas elaborated by the traditional nixtamalization process.