One of the most important forms of preharvest damage to wheat in Iran and some other countries is caused by sunn pest Eurygaster integriceps . This damage results in low baking performance due to bug proteolytic enzymes’ injected into wheat. However; the weak wheat proteins could recover their native stable form using improvers such as ascorbic acid so that it would be possible to use the flour of damaged wheat to reduce the economical losses. In this study, proximate analysis along with physical measurements were done for the three varieties named Alvand, Backcross Roshan and Mahdavi, which were a blend of damaged and sound wheat. The effect of bug protease on wheat quality was also investigated, using chemical procedures and electrophoresis. Finally effect of ascorbic acid improver effect at two levels, 100 and 200 ppm, on farinogaraph characteristics were investigated. Results indicated that wet and dry gluten, gluten index, zeleny sedimentation value and disulfide groups in all varieties significantly (p 0.05) decreased and degree of gluten hydrolysis, sulfhydryl content and total reducing agents increased due to the damage. Effect of ascorbic acid in all the three varieties on wet and dry gluten content, gluten index, total reducing substances and sulfhydryl and disulfide groups were significantly different. Electrophoresis results of sound and damaged wheat flour of the three varieties revealed main protease effect on HMW-GS, however; LMW-GS and gliadins were slightly affected by the enzyme. It was evidenced that by disappearing of high molecular weight bands from electrophoregram, bands of low molecular weight compounds are developed. Finally addition of ascorbic acid, increased water absorption, dough development time, dough stability, arrival time, time to break down and valorimetric value and decreased mixing tolerance index and dough degree of softening in the farinograms that confirmed ascorbic acid improvement on flours studied.
