Effect of temperature and screw speed on stability of fumonisin B-1 in extrusion-cooked corn grits

Corn grits spiked with fumonisin B-1 (FB1) at a level of 5 mu g/g were extr usion cooked in a corotating twin-screw extruder at different temperatures (140, 160, 180, and 200 degrees C) and screw speeds (40, 80, 120, and 160 r pm). Good recoveries of FB1 were obtained from the nonextruded as well as t he extruded grits by using high-performance liquid chromatography. Both the barrel temperature and the screw speed significantly (P less than or equal to 0.05) affected the extent of fumonisin reduction in extruded grits. As expected, the FB1 recovered decreased with an increase in temperature and a decrease in screw speed. The amount of FB1 lost from cooking grits at the different extrusion parameters used in this study ranged from 34 to 95%. Ab out 46-76% of the spiked FB1 was lost when the grits were cooked at tempera tures and screw speeds that resulted in acceptable product expansion and co lor.