Bt Detection, Protein, Lipids and Toxic Antinutritional Substances in Mexican Maize

The maiz (Zea mays L.) can contain polyphenols and mycotoxins; therefore, the genetic engineering technology has developed Bt maize which has recombinant proteins without risky substances chemical. The aflatoxins are the most toxic mycotoxins capable of producing cancer and decreasing the immune response in humans. Tannins affect the nutritional value of maize and hepatic and renal disfunction in high levels. The aim of this study was to identify the presence of Bt maize events and compare the content of aflatoxins and soluble polyphenol compounds. Twenty-five samples of maize grain were collected, 12 hybrid maize and 13 local varieties, from Hidalgo, Mexico and Morelos. Samples were analyzed for Cry1Ab/Cry1Ac, using lateral flow strip method, crude protein and lipids by standard methods. Aflatoxins were assessed by commercial Elisa kit, and 30 samples maize from Mexico City were identified by HPLC-FD and polyphenol compounds by UV-Vis spectrophotometry method. The data were grouped in a completely random model and an analysis of variance was performed. The results indicated that 44.5% of hybrid maize were positive to Bt-Cry1Ab/1Ac proteins, containing 9.02% ± 2.5 lipids and 11.33% ±2.2 crude protein, 189 ± 0.92 mg/g of polyphenol compounds and 6.36 ± 3.3 µg·g aflatoxins. The local maize samples (55.5%) were negative to Bt-Cry1Ab/Cry1Ac, containing 8.68%±0.90, 6.14% lipids ± 2.3, 273 ± 0.40 mg/g polyphenol compounds and 7.15 ± 3.3 µg·kg of aflatoxins. In 13 hybrid maize from Mexico City, we found 5.43 µg/kg in a range of 0 to 10.45 µg/kg and 3.35 µg/kg (0-7.91) in local varieties.   In conclusion, we observed an improvement of lipids and protein content (nutritional composition) in hybrid maize positive to Bt proteins, with a decrease in polyphenol compounds content              comparing with some local varieties without Bt proteins.  The effectiveness of Bt maize expressing the Cry1Ab/ Cry1Ac in reducing aflatoxin contamination was not observed, therefore, additive effects of aflatoxins contamination in maize Bt-Cry need to be further investigated in chronic disease development.

Author(s) Details

Peña Betancourt Silvia Denise
Laboratorio de Toxicología, Departamento de Producción Agrícola y Animal, UAM-Xochimilco, México, D.F., Mexico.

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