Effect of Aelia spp. and Eurygaster spp. damage on wheat proteins

The effect of Aelia spp. and Eurygaster spp. wheat bugs on the protein fractions of different wheat cultivars has been studied by size-exclusion high-performance liquid chromatography (SE-HPLC) and free-zone capillary electrophoresis (FZCE). Those methods were used to quantify and characterize the extent of protein modification. A decrease in the amount of alcohol-insoluble polymeric proteins along with an increase in the alcohol-soluble polymeric proteins and gliadins were observed in damaged wheat. The high molecular weight (HMW) and low molecular weight (LMW) glutenin fractions were barely detected in the incubated damaged wheat from some cultivars, which indicated hydrolysis of those proteins by the bug proteinases. In damaged wheats, both incubated and unincubated, gliadin electrophoregrams revealed the presence of some new peaks with mobilities similar to the omega gliadins. The overall results suggest that the bug proteinases are potent enzymes that appear to be nonspecific because they hydrolyze all gluten proteins.