Superheated steam reduction of deoxynivalenol in naturally contaminated wheat kernels

Contamination of wheat with the Fusarium mycotoxin deoxynivalenol (DON) is a concern to the ethanol industry as it is stable during most processing operations and will be concentrated in the spent grains, which are potentially a valuable feedstock. Superheated steam at four processing temperatures (110, 135, 160, and 185 °C), three steam velocities (0.65, 1.3, and 1.5 m/s), and processing times of 2–15 min were used to treat wheat kernels naturally contaminated with DON to find the best processing parameters for the reduction of DON. A commercial enzyme-linked immunosorbent assay (ELISA) kit was used to determine DON levels in the wheat samples. Samples became increasingly toasted, displaying a brown color with increasing processing temperatures and times, and became friable after processing at temperatures of 160 and 185 °C. Only samples processed at 185 °C and 1.3 m/s exhibited any starch gelatinization. Significant (P < 0.05) reductions in DON levels were seen at 160 and 185 °C but were not generally seen at 110 and 135 °C and the effect of velocity was not significant (P > 0.05). Reductions of up to 52% were achieved at 185 °C and 6 min processing time and were due only to thermal degradation and not to solubilization and extraction.