Protein polymerization and water mobility in whole-wheat dough influenced by bran particle size distribution

- Four bran particle size distributions were obtained by fine-grinding treatment.
- Moderate bran particle size promoted mixing stability of whole-wheat dough (WWD).
- Bran particle size influenced the microstructure and protein polymerization in WWD.
- Secondary structure and T2 time curves verified the changes by bran particle size.
- Bran fine-grinding treatment modified protein polymerization and gluten development.

The influences of bran particle size distribution on the protein polymerization and water mobility in whole-wheat dough (WWD) were investigated. Four bran particle size distributions were obtained by fine-grinding treatments and the mean particle sizes of reconstituted whole-wheat flour (WWF) were 242, 160, 114, and 45 μm, respectively. Mixolab parameters showed that WWF water absorption was increased with reduced bran particle size, and the 160 μm group exhibited a higher stability than any other WWF group. A more continuous gluten matrix and a more compact structure were observed in the 160 μm group due to its moderate bran particle size. Protein secondary structure analyses indicated the increased β-sheet conformation and reduced β-turns structure in the 160 μm group, demonstrating a more polymerized and stable gluten network formed. Additionally, 1H NMR measurements showed larger populations of tightly bound water in WWD due to the presence of arabinoxylan, and confirmed the strengthened gluten strength in the 160 μm group by indicating increased water availability to gluten proteins. The results suggest that modifying bran particle size is a potential method for protein polymerization enhancement and gluten formation improvement in WWD, but appropriate bran particle size is needed to strengthen gluten network.