Effects of Tartary Buckwheat Bran Flour on Dough Properties and Quality of Steamed Bread

Steamed bread is a traditional staple food of China. Replacing wheat flour (WF) with Tartary buckwheat is expected to improve the nutritional value of steamed bread. In this study, Tartary buckwheat flour (TBF), Tartary buckwheat bran flour (TBBF), and Tartary buckwheat core flour (TBCF) were prepared, their composition and physicochemical properties were compared. It was found that TBBF had higher protein and rutin contents, so its antioxidant activity and dough rheological properties were obviously superior to those of TBF and TBCF. When TBBF was mixed with WF, its weight proportion in the blend (W(bran)) had a significant effect on the dough rheological properties. When W(bran) was 30%, the dough had the optimal mixing tolerance, and when W(bran) exceeded 30%, it caused dilution effect, weakening the gluten network. With the increase of W(bran), the color of the steamed bread developed by the TBBF–WF blend gradually darkened and yellowed, the specific volume declined, and its hardness, gumminess, and chewiness ascended gradually. The appropriate addition of TBBF (W(bran) = 10% and 30%) was beneficial to cell diameter and volume of steamed bread, but the further rise of W(bran) would destroy its gas retention ability. The predicted glycemic index (pGI) of steamed bread declined significantly with the increasing W(bran).