Utilization of sorghum brans and barley flour in bread

Abstract

White, brown, and black sorghum brans, wheat bran, and a waxy barley flour were each substituted for 0-30% of wheat flour in a bread formula. Each of the brans were then combined with the barley flour and substituted for a total of 20-25% of the wheat flour in the bread formula. The brans and barley flour were analyzed for dietary fiber, phenols, tannins, anthocyanins, and ORAC values. Effects of substitutions on bread qualities were evaluated and optimum levels of use were determined. All the brans contained similar levels of dietary fiber (41-48%). The brown sorghum bran was highest in tannins, phenols, and ORAC value, and the black sorghum bran was highest in anthocyanins. The barley flour contained significantly less dietary fiber (13.9%) and higher levels of β-glucans (4.4%) than the brans. More than 15% brown or black sorghum bran in the bread formula significantly reduced specific volumes. Interactions between tannins in the brown sorghum bran and gluten proteins, and puncturing of air cells by sharp glume fragments in the black sorghum bran were determined to adversely affect dough structure. The optimum usage level of 15% was chosen for the brans based on bread qualities and dietary fiber levels (~3g/serving). Brown and black sorghum brans added significant levels of antioxidants/phenolic compounds to the bread and gave a dark brown color. The optimum level of 20% barley flour in the bread added significant levels of soluble fiber (0.9g/serving), minimally affected color, and did not contribute excessive chewiness. Acceptability scores for 20% barley flour bread were not significantly different from those for wheat bran or non-waxy barley flour bread. Breads containing the optimum combinations of 10% barley flour/10% bran had specific volumes similar to those for 15% bran and 20% barley flour breads, and were good sources of total (~3g/serving) and soluble dietary fiber (0.7g/serving). Those with brown or black sorghum bran were significantly higher in phenolic compounds. The use of sorghum brans and barley flour in bread adds soluble and insoluble dietary fiber as well as antioxidants. Breads containing these beneficial ingredients could be promoted as nutraceuticals or functional foods.