Influences of hydrothermal and pressure treatments on compositional and hydration properties of wheat bran and dough mixing properties of whole wheat meal

Authors: LEE, YU YOUNG - Korean Rural Development Administration; MA, FENGYUN - The Ohio State University; Byars, Jeffrey; Felker, Frederick; Liu, Sean; MOSIER, NATHAN - Purdue University; LEE, JI HAE - Korean Rural Development Administration; Kenar, James - Jim; Baik, Byung-Kee

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2021
Publication Date: 2/4/2021
Citation: Lee, Y., Ma, F., Byars, J.A., Felker, F.C., Liu, S.X., Mosier, N.S., Lee, J., Kenar, J.A., Baik, B.V. 2021. Influences of hydrothermal and pressure treatments on compositional and hydration properties of wheat bran and dough mixing properties of whole wheat meal. Cereal Chemistry. 98(3):673-682. https://doi.org/10.1002/cche.10411.
DOI: https://doi.org/10.1002/cche.10411

Interpretive Summary: Bran, a residue of wheat milling in the production of refined flour, is rich in dietary fibers, minerals and phenolics and thus increases the nutritional quality of whole wheat foods and provides numerous health benefits to consumers. The presence of bran in whole wheat meal, on the other hand, causes some unwanted changes in the processing properties and negatively affects product quality and consumer acceptance. Modifying wheat bran to mitigate its undesirable characteristics and blending it with wheat flour to prepare whole wheat meal would be logical approaches for improving product quality and consumer acceptance. Combinations of heat, moisture and pressure treatments including autoclaving, roasting, jet cooking, extrusion, puffing and high-temperature-high-pressure cooking all increased the water absorbing and retaining capacities, and soluble dietary fiber content, but differently affected the microstructure of particles, particle size distribution, bulk density, total phenolic content and total dietary fiber content of wheat bran, and the dough mixing properties of bran-wheat flour blends. Jet cooking induced the smallest change in bran color, while extrusion was most effective at increasing the bulk density, total phenolic content and soluble dietary fiber content of wheat bran, as well as at improving the dough mixing time of bran-wheat flour blends. The results of this study catalog the changes in the functional properties of bran with each treatment and allow food manufacturers to identify the bran treatments that enhance the bran characteristics necessary for the preparation of whole wheat foods with improved quality and sensory acceptance.

Technical Abstract: Background and objectives: Wheat bran delivers many nutritional benefits to consumers but negatively affects dough-mixing properties, subsequently decreasing product quality and acceptability. The effects of autoclaving, roasting, jet cooking, extrusion, puffing and high-temperature-high-pressure (HTHP) cooking of wheat bran on its physical and functional properties and on dough-mixing properties of whole wheat meal (WWM), prepared by blending flour and bran, were determined to identify appropriate bran pretreatment methods. Findings: Water absorption index, water retention capacity and soluble dietary fiber (SDF) content of bran significantly increased by 0.3-1.0 g/g, 0.2-1.6 g/g and 0.6-1.7%, respectively, with all treatments. Bulk density and total phenolic content (TPC) of autoclaved, extruded and HTHP-cooked brans increased by 0.19-0.23 g/mL and 1.2-1.5 mg/g, respectively, while those of roasted and jet-cooked brans decreased by 0.02-0.32 g/mL and 0.5-0.6 mg/g, respectively. Only extruded bran significantly increased midline peak time (MPT) of WWM by 0.5 min. Conclusions: Extrusion was most effective at increasing the TPC, SDF content and bulk density of bran and the MPT of WWM. Significance and novelty: The results catalog the changes in bran functional properties with each treatment and allow food manufacturers to identify the treatments that enhance bran characteristics necessary for making improved-quality whole wheat foods.