Effect of bran particle size on rheology properties and baking quality of whole wheat flour from four different varieties

Authors: LI, CHENG - Kansas State University; Tilley, Michael - Mike; Chen, Yuanhong - Richard; SILVERU, KALIRAMESH - Kansas State University; LI, YONGHUI - Kansas State University

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2023
Publication Date: 1/21/2023
Citation: Li, C., Tilley, M., Chen, Y., Silveru, K., Li, Y. 2023. Effect of bran particle size on rheology properties and baking quality of whole wheat flour from four different varieties. LWT - Food Science and Technology. https://doi.org/10.1016/j.lwt.2023.114504.
DOI: https://doi.org/10.1016/j.lwt.2023.114504

Interpretive Summary: Consuming whole grain foods can reduce the risk of developing type II diabetes, cardiovascular diseases, obesity, and several other diseases The benefits of whole grains are related to the functional components existing in the bran and germ, mainly dietary fibers and phytochemicals including phenolic compounds. Due to the multiple health and nutritional benefits of whole wheat products, many previous efforts have been made to understand and optimize the quality parameters of whole wheat flour and bread. Compared to white bread, making high-quality whole-wheat bread can be more challenging, due to the complex flour composition and presence of brans and germs that impact gluten development and dough mixing. Bran particle size is one of the dominating factors affecting the bread-making quality of whole wheat flour. It is largely unknown how the particle size of bran in whole wheat flour influences its technological properties of the dough and baking characteristics. In this study, the effect of bran particle size on whole wheat flour dough and bread-making performance was investigated using four different hard winter wheat varieties (Zenda, Tatanka, AG Gallant, and Turkey Red) with protein levels ranging from 9 to 15%. Each wheat sample was first milled with a laboratory roller mill to collect the strait-grade flour and the bran (including shorts). The bran from each variety was further ground with different mill settings to produce brans with the same composition but five different particle size ranges (coarse, coarse to medium, medium, medium to fine, and fine) that ranged from 590.5 to 159.7 µm. Each bran fraction was blended with the corresponding white flour to generate the whole wheat flour (WWF). Whole wheat flour with medium size bran (315–363 µm) produced relatively soft bread with larger loaf specific volume. Results also revealed that using most fine bran had a negative influence on the hardness, chewiness and color properties (darker color) of the bread. Moreover, larger specific loaf volume was observed for white bread with a relatively higher protein content in the flour, but this was not always associated with the trend for the whole wheat flours. Results demonstrated that reducing wheat bran to medium particle sizes (315–363 µm) is effective in improving the bread-making quality of whole wheat flour. The findings of this study contribute to the standardization of whole flour bran particle sizes for quality assessment and effective industrial production. Future work should evaluate more wheat varieties to understand the associations between bread-making properties of white and whole wheat flours.

Technical Abstract: The potential health benefits of consuming whole grain foods are increasingly attracting customers’ interest. In this study, the effect of bran particle size on whole wheat flour dough and bread-making performance was investigated using four different hard winter wheat varieties (Zenda, Tatanka, AG Gallant, and Turkey Red) with protein levels ranging from 9 to 15%. Each wheat sample was first milled with a laboratory roller mill to collect the strait-grade flour and the bran (including shorts). The bran from each variety was further ground with different mill settings to produce brans with the same composition but five different particle size ranges (coarse, coarse to medium, medium, medium to fine, and fine) that ranged from 590.5 to 159.7 µm. Each bran fraction was blended with the corresponding white flour to generate the whole wheat flour (WWF). Mixolab analysis revealed white flour had a lower water absorption but higher amplitude and retrogradation values than the corresponding whole wheat flours. Larger specific loaf volume was observed for white bread with a relatively higher protein content in the flour, but this was not always associated with the trend for the whole wheat flours. For most wheat varieties, the bread from WWF with the fine bran had the lowest specific loaf volume, darker crumb color, and larger hardness value than bread made with white flour or with WWF of other particle sizes. WWF with medium bran size (315–363 µm) was more suitable for bread production. Our findings will help to standardize the whole wheat flour bran particle sizes for whole wheat bread quality control and industrial production.