|Voss, Kenneth - Ken|
|Gelineau-van Waes, Janee|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2009
Publication Date: 6/15/2009
Citation: Voss, K.A., Burns, T.D., Ryu, D., Jackson, L.S., Bullerman, L.B., Riley, R.T., Gelineau-Van Waes, J. 2009. A bioassay approach for determining the effect of cooking on fumonisin toxicity. Proceedings of presentations for the German Society for Mycotoxin Research Annual Workshop, Muenster, Germany, June 2009. Interpretive Summary: Abstract - no summary required.
Technical Abstract: Fumonisins are considered potential risk factors for cancer and congenital malformations known as neural tube defects (NTD) in populations that consume maize as a diet staple. Cooking variably reduces fumonisin concentrations. However, fumonisin concentrations and potential toxicity of foods might be underestimated due to formation of novel matrix binding or degradation products (Humpf, H.-U.; Voss, K. A. 2004, Effects of food processing on the chemical structure and toxicity of fumonisin mycotoxins. Mol. Nutr. Food Res. 48:255-269). Therefore, rodent bioassays incorporating sphingoid base analyses and histologic appearance of target organs as endpoints have been used to determine the effectiveness of selected cooking methods to decrease fumonisin toxicity. 1) Nixtamalization (alkaline cooking) of F. verticillioides culture material (CM) reduced its fumonisin B1 (FB1) concentrations about 75 percent. Reduction increased to 95 percent when the CM was mixed with ground maize before cooking. When equivalent amounts of uncoooked CM and nixtamalized CM were fed to rats, hepatotoxicity (increased tissue sphinganine and apoptotic lesions) induced by the uncooked CM was significantly more severe than that caused by the nixtamalized CM. In contrast, sphingolipid effects and lesions were absent in rats fed the nixtamalized CM-ground maize mixture. 2) Fumonisin B1 (FB1) induces NTD when given intraperitoneally (5 mg/kg (=7 µmol/kg) BW or higher) to LM/Bc mice at the critical time (E7-8.5) for neural tube closure. Using this bioassay, hydrolyzed FB1 (HFB1) did not cause NTD at doses up to 20 mg/kg (49 µmol/kg). The 20 mg/kg dose of HFB1 disrupted maternal sphingolipid metabolism slightly whereas 10 mg/kg HFB1 (25 µmol/kg) did not. In comparison, a dose of 10 mg/kg (14 µmol/kg) F¬B1 markedly disrupted maternal sphingolipid metabolism. 3) Extrusion cooking, which combines high heat and pressure, is a proposed method for reducing fumonisins in maize-based products. It reduced FB1 concentrations of spiked grits and two batches of F. verticillioides-fermented grits from 10 to 28 percent. Addition of glucose to the grits before extrusion increased reductions to 75-85 percent and facilitated FB1-sugar binding; 52-68 percent of the FB1 was recovered as the N-(deoxy-D-fructos-1-yl) FB1 binding product. In a three week rat feeding bioassay, extrusion with glucose supplemen-tation reduced the severity of kidney lesions induced by one batch of the fermented grits. The reduction was attributed to the lower FB1 concentration (1.9 ppm) in the diet prepared from this batch of grits compared to the diets formulated with equivalent amounts of the uncooked (12.7 ppm or higher) or other cooked preparations (3.3 ppm or higher). These bioassays indicate that nixtamalization effectively reduces FB1 in cooked products and provide evidence that the beneficial effect likely involves interactions between FB1 and maize matrix components in addition to hydrolysis of the mycotoxin. Rodent bioassays will also be useful in further studies to define the conditions under which other cooking methods, including extrusion with glucose supplementation, will safely reduce fumonisins in maize-based products.