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

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 B 1 (AFB 1 ) by 94%, aflatoxin M 1 (AFM 1 ) by 90% and aflatoxin B 1 -8,9-dihydrodiol (AFB 1 -dihydrodiol) by 93%. The extrusion process reduced levels of AFB 1 by 46%, AFM 1 by 20% and AFB 1 -dihydrodiol by 53%. Extrusion treatments with 0, 0.3 and 0.5% lime reduced AFB 1 levels by 46, 74 and 85%, respectively. The inactivation of AFB 1 , AFM 1 and AFB 1 -dihydrodiol in the extrusion process using lime together with hydrogen peroxide showed higher elimination of AFB 1 than treatments with lime or hydrogen peroxide alone. The extrusion process with 0.3% lime and 1.5% 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.