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.