Whole wheat bread: Effect of bran fractions on dough and end-product quality

Authors: KHALID, KHAIRUNIZAH - North Dakota State University; Ohm, Jae-Bom; SIMSEK, SENAY - North Dakota State University

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2017
Publication Date: 3/16/2017
Citation: Khalid, K.H., Ohm, J., Simsek, S. 2017. Whole wheat bread: Effect of bran fractions on dough and end-product quality. Journal of Cereal Science. 78:48-56.

Interpretive Summary: Consumption of whole-wheat based products is encouraged due to its important nutritional elements that beneficial to human health. However, processing of whole-wheat based products, such as whole-wheat bread, results in poor end-product quality. Bran was postulated as the major problem. In this study, four major bran components including lipids, extractable phenolics, hydrolysable phenolics, and fiber were evaluated for their specific functionality in flour, dough and bread baking. Interestingly, bran fiber was identified as a single main factor that had highly significant impact on all the flour, dough, and baking parameters measured in this experiment. Specifically, presence of fiber in bread-making increased water absorption and decreased mixing stability. Hydrolysable phenolics that mainly compose water-insoluble phenolics and fiber synergistically had negative impact on gluten and dough quality. Also, fiber and hydrolysable phenolics were the main factors that significantly impacted bread loaf volume. Reconstituted breads prepared without fiber or hydrolysable phenolics had higher loaf volume than white bread. Overall, the influence of bran components on bread-making quality seemed very complex. The result of this study will be a helpful reference for further research to improve whole wheat bread quality.

Technical Abstract: Consumption of whole-wheat based products is encouraged due to its important nutritional elements that beneficial to human health. However, processing of whole-wheat based products, such as whole-wheat bread, results in poor end-product quality. Bran was postulated as the major problem. In this study, four major bran components including lipids, extractable phenolics, hydrolysable phenolics, and fiber were evaluated for their specific functionality in flour, dough and bread baking. The experiment was done by reconstitution approach using the 24 factorial experimental layout. Interestingly, bran fiber was identified as a single main factor that had highly significant impact on all flour, dough, and baking parameters measured in this experiment. Fiber and hydrolysable phenolics synergistically had negative impact on gluten index and dough quality. Also, fiber and hydrolysable phenolics were the main factors that significantly impacted bread loaf volume. Reconstituted breads prepared without fiber or hydrolysable phenolics had higher loaf volume than white bread. Overall, influence of bran components on bread-making quality seemed very complex since analysis of variance showed that interaction of all four bran components (lipid, extractable and hydrolysable phenolics, and fiber) was highly significant (P<0.05) to cause changes in farinograph parameters, gluten index, baking parameters, and gassing power.