Effects of different extrusion conditions on the chemical and toxicological fate of fumonisin B1 in maize: a review

Authors: JACKSON, LAUREN - Food And Drug Administration(FDA); Voss, Kenneth; RYU, DOJIN - Texas Woman'S University

Submitted to: World Mycotoxin Journal
Publication Type: Review Article
Publication Acceptance Date: 7/19/2012
Publication Date: 8/17/2012
Citation: Jackson, L.S., Voss, K.A., Ryu, D. 2012. Effects of different extrusion conditions on the chemical and toxicological fate of fumonisin B1 in maize: a review. World Mycotoxin Journal. 5(3):251-260.

Interpretive Summary: Fumonisins are toxins produced by molds found in corn (maize). Fumonisin B1 (FB1) is the most common and is a potential risk factor for certain cancers or birth defects. Minimizing exposure is therefore desirable. Extrusion cooking, a method that combines high temperatures and pressures, reduces fumonisin levels in processed corn products and reductions are greater if glucose is mixed with the corn prior to cooking. However, the chemical fate of the fumonisins during extrusion is not fully understood. The potential toxicity of any unknown fumonisin degradation products or so-called "masked" or "hidden" fumonisins (those associated with the food matrix in a manner making them undetectable) that form during extrusion is also unknown. Therefore, to determine how extrusion affects fumonisin toxicity, batches of FB1-contaminated corn-grits that were (a) uncooked, (b) extrusion cooked, or (c) extrusion cooked with glucose supplementation under various processing conditions were fed to rats. Depending on cooking conditions, FB1 concentrations in the extruded grits were reduced by 21-94%. The uncooked grits caused kidney damage and lipid metabolism changes that are typical of FB1 exposure. These effects were relatively less severe in animals fed extruded grits whereas the least severe effects (including the absence of kidney injury in one group) were found in rats fed grits processed by extrusion with glucose supplementation. These bioassay results show that extrusion cooking with glucose supplementation effectively reduces the toxic potential of fumonisins in corn.

Technical Abstract: A series of experiments to investigate the chemical and toxicological fate of fumonisin B1 (FB1) under different extrusion conditions using both single- and twin-screw extruders is described. Maize grits were contaminated with FB1 at different concentrations by fermentation with Fusarium verticillioides M-2552. They were then processed by extrusion with or without glucose (10%, w/w) supplementation. The chemical fate of fumonisins was investigated by measuring FB1, its analogs, and reaction products with a mass balance approach while the relative toxicity of the grits preparations was determined by rat feeding trials. FB1 in the contaminated grits was reduced by 21-37% and 77-87% in the absence and presence of 10% (w/w) glucose, respectively, during single-screw extrusion. Greater reductions of 64-72% and 89-94% were achieved by twin-screw extrusion. Mass balance analysis showed that most of the fumonisin in grits extruded without glucose was recovered as FB1, whereas the FB1-glucose reaction product, N-(deoxy-D-fructos-1-yl)fumonisin B1 was the prevalent form after extrusion with glucose. After both single- and twin-screw extrusion, with or without glucose, hydrolyzed FB1 was a minor species. Reduced FB1 concentrations in extruded grits and the even lower concentrations in grits extruded with glucose resulted in a dose-dependent (based on calculated daily FB1 intakes) reduction of toxicity as shown by the less severe apoptotic lesions and sphingolipid effects that were found in the kidneys of the rats. In summary, extrusion processing, especially with glucose supplementation, is potentially useful to reduce FB1 concentrations and toxicity of contaminated maize.