Effects of the hydrothermally treated wheat bran on the quality and nutritional value of bread

In our country the use of wheat bran as a by-product has increased in bread production due to increasing health problems and consumer consciousness towards more beneficial and nutritious products. The use of bran in bread production causes physical, technological and sensory problems. In this study hydrolyzate was obtained by hydrothermal treatment at 150°C for 30 minutes from the wheat bran which has low economic value and the obtained hydrolyzates were added to the dough kneading water at different ratios (10, 20, 30, 50 and 100%) and bread productions were carried out. Physicochemical (weight, volume, hardness, moisture, protein, fat), functional (dietary fiber, antioxidant activity, total phenolic contents), rheological, nutritional (slowly digestible starch, rapidly digestible starch, starch hydrolysis index) and sensory properties of bread were investigated. It was found that the addition of hydrolyzate to dough kneading water improves the physical properties (height, volume, specific volume) of bread compared to the direct addition of bran. The addition of hydrolyzate was leaded to an increase in the contents of especially soluble dietary fiber, antioxidant activity (FRAP, TEAC and DPPH) and total phenolic materials, compared to bread without addition of bran. It was found that the addition of hydrolyzate reduces the hardness of the bread, increases the content of slow digestible starch, and decreases the content of rapid digestible starch. It was determined that the rheological properties (stability, development time, etc.) were adversely affected after the addition of 50% and 100% hydrolyzate, but these adverse effects remained at lower levels than the coarse and fine bran additions. Also, the addition of hydrolyzate was found to increase the level of sensory acceptability relative to coarse and fine bran-added breads. The results show that hydrothermally treated wheat bran could minimize the rheological, physical and sensory problems caused by the direct bran addition in bread production and that this could improve the functional and nutritional properties of the bread.