Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/30/2002
Publication Date: 6/30/2002
Citation: ROSELL, C.M., AJA, S., BEAN, S., LOOKHART, G.L. EFFECT OF AELIA SPP. AND EURYGASTER SPP. DAMAGE ON WHEAT PROTEINS. CEREAL CHEMISTRY. 2002. Interpretive Summary: Wheat is a major food crop around the world. Differences in hardness of the wheat kernel and in other physical and chemical properties are used to classify wheat for end-use. The flour that is made from each different wheat classes is used for different food products. For instance, soft wheats are used to make cookies and cakes whereas hard wheats are used for breads and hard rolls. One of the most important components in wheat flour, for each of those products, is the protein fraction. In the field, wheat plants are attacked by various insects and other predators. One set of these predators, Aelia spp. and Eurygaster spp. wheat bugs, was found to break down all wheat gluten proteins. When the proteins are broken down by those bugs, the flours can no longer be used to produce the normal products. Therefore, it is important to the entire wheat food industry to be able to detect the presence of wheat bug damage.
Technical Abstract: 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 non-incubated, gliadin electrophoregrams revealed the presence of some new peaks with mobilities similar to the gliadins. The overall results suggest that the bug proteinases are potent enzymes, which appear to be nonspecific because they hydrolyze all gluten proteins.