Enzymes of wheat flour have an important role on the quality of various backing products, especially bread. The knowledge of their activites can assist us to produce the high quality products. On the other hand, the most wheat flours in the countery have low α-amylase activity. Therefore, optimization of flour α-amylase activity is important for production of high quality bread. In the present work, chemical properties of three wheat flours varieties (Mahdavi, Kavir and M7318 that are produced in Isfahan province) were investigated. To show the changes of α-amylase activities, the activities of enzyme were measured during the germ growth times up to 72 hours. α-amylase activity of flours was also optimized according to falling number 250. The effect of this optimization on the bread texture in four different times after baking were then evaluated. The results showed that all three varieties had lower levels of α-amylase activity than the optimum level. The results indicated an increase in the activity of α-amylase during the growth of germ up to 72 hours. The results of the determination of the best blending percentage of germinated wheat flour with baking flour indicated that optimization of α-amylase activity is essential in terms of both wheat varieties of flour and germination times of wheat germ. Bread texture analysis indicated that bread produced with optimized α-amylase activity flours using appropriate percentage of germinated wheat flour have softer texture and lower staling. Wheat variety had also an important effect on staling so that bread produced with Kavir variety flour had softer texture than other varieties. Breads produced with optimized flour using 72-hours germinated wheat flour had softer texture than the breads made by optimized flours with other germination times.

Keywords: α-amylase, Staling bread, Germinated wheat flour

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