Effect of insoluble dietary fibers on dough properties and bread quality

• 1、School of Food Science and Technology,Jiangnan University,214122

Abstract：In order to explore the mechanism of the influence of the addition of insoluble dietary fibers on bread quality, the present study was initiated. soybean citrus and wheat fibers were used to partially replace the major raw material (wheat flour) in the basic formula of bread. Dietary fiber properties and their impact on bread quality (specific volume, texture, crumb structure of bread, etc.) were investigated and the resultant difference on the bread quality was further elucidated by evaluating the dough properties due to the addition of each fiber material. Thus, the dough properties (rheological properties, gluten content, chemical forces, etc.) were determined and the relationship among bread quality, dough properties and dietary fiber properties established. The results showed that the specific volume of the bread was reduced, while the hardness, and pores became larger and sparse after adding dietary fiber. Hence, the overall quality of bread decreased,and the degree of decline from high to low was soybean fiber, citrus fiber and wheat fiber. For example, the specific volume was decreased by 1.55,1.54 and 0.59 mL/g, respectively.The hardness was increased by 514,387 and 262g.The evaluation of dough properties found that the addition of dietary fiber increased the water absorption, dough formation time, weakening degree and viscoelastic modulus of wheat flour, which reduced the stability time, tensile properties and fermentation characteristics of the dough. There was a correlation between different doughs and the bread quality. For example, the water absorption of the three dietary fiber was increased by 19.05%, 13.90%,9.90%, respectively. Further studies found that the high water holding capacity and swelling capacity of dietary fiber led to a significant decrease in wet gluten content (4.39% - 9.84%) and disulfide bond content (2.22% - 7.21%) in dough, diluting the gluten protein and also destroyed the gluten network structure, causing a great difference in bread and dough properties.

Keywords： Insoluble dietary fiber bread quality dough properties water holding capacity swelling capacity