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 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.

Aflatoxin in Agricultural Commodities and Herbal Medicine

“…Other tortilla production which involved the use of calcium hydroxide showed only a limited effect on Aflatoxin content (Magan, 2004). Generally, similar results were obtained by Elias-Orozco et al (2002) while they used the extrusion process in the production of corn tortillas. They found that the use of 0.3% lime and 1.5% hydrogen peroxide was the most effective reducing process (Elias-Orozco, Castellanos-Nava, Gaytan-Martinez, Figueroa …”

The fate of mycotoxins during thermal food processing

“…13 In another report, this traditional nixtamalization process reduced levels of AFB 1 by 94% and AFB 1 -8,9-dihydrodiol by 93%. 14 Roasting is considered one of the most effective methods of reducing aflatoxin levels in certain commodities, such as peanuts and coffee in particular, with average reductions in the aflatoxin content of peanuts ranging from 45% to 83% following dry roasting being reported. 15 Pluyer et al 16 have reported that oven roasting of naturally contaminated peanuts at 150…”

Reduction of aflatoxin B1 during tortilla production and identification of degradation by-products by direct-injection electrospray mass spectrometry

“…14 Many reports have demonstrated that nixtamalización process inactivated AFB 1 by 85-95%. 6,15 However, for high aflatoxin contamination (520µg/kg), the percentage of AFB 1 inactivation was reduced to 93%, 6 therefore 7% of AFB 1 remains in the tortilla, representing a health hazard. 16 Mexican people would daily ingest 0.95µg of AFB 1 for each tortilla and 4.75µg AFB 1 /5 tortillas.…”