This research contributes to the overall goal of determining the fate of fumonisins in grains and processed grain-based feed and food products. Within this framework, the specific objective is twofold: (a) to determine chemical fate of fumonisin B1 (FB1) when glucose supplemented, fumonisin-contaminated corn grits are cooked by extrusion and (b) to determine the effectiveness of this extrusion cooking method for reducing the in vivo toxicity of the contaminated grits.
Approach: Fumonisin-contaminated grits will be produced by fermenting corn flaking grits with a fumonisin-producing Fusarium isolate under controlled conditions The contaminated grits will then be cooked by extrusion with addition of glucose to the extrusion dough. Uncooked fermented grits and the extrusion product will be evaluated by ELISA, HPLC and mass spectral methods to determine the effect of extrusion on fumonisin (fumonisin B1, B2) concentrations. The type and the amounts of known fumonisin reaction products, including putatively nontoxic fumonisin-sugar reaction products, will also be chemically determined. The unprocessed grits and extruded product will be further analyzed for the presence of matrix-bound fumonisins using a technique involving base hydrolysis (liberates bound FB1 as hydrolyzed FB1) of the materials followed by quantification of the liberated hydrolyzed FB1 using HPLC or mass spectral methods. A mass balance approach will be used to determine recovery of fumonisins. <P>The toxicity of the extruded material will be compared to that of unprocessed (not extruded) and extruded uncontaminated grits and unprocessed contaminated grits to determine the extent to which the extrusion cooking process reduces toxicity. This will be done using an established bioassay in which equal amounts of the materials are fed to rats and their effects evaluated by serum chemical, tissue sphingolipid profile, and histopathological endpoints indicative of fumonisin toxicity.