Abstract: In order to make efficient use of wheat bran and to improve its quality characteristics, wheat bran was physically modified by ultrafine grinding combined with gradient glutenin addition in this study. The changes in physicochemical and functional characteristics such as particle size distribution, color, hydration characteristics, filling characteristics and flow characteristics of wheat bran ultrafine powder were analyzed. The structural changes were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results showed that the addition of glutenin during the ultrafine grinding of wheat bran significantly increased the whiteness of wheat bran ultrafine powder, significantly reduced the particle size of wheat bran and enhanced its uniformity (P < 0.05), and improved the agglomeration behavior of wheat bran. The oil holding capacity, solubility and swelling capacity of wheat bran were significantly increased by ultrafine grinding combined with gradient glutenin addition (P < 0.05). With increasing glutenin addition, the bulk density and tap density of wheat bran ultrafine powder increased, and the angle of repose and slip angle decreased, reflecting improved filling and fluidity of wheat bran. Ultrafine grinding combined with moderate glutenin addition (2%–4%) resulted in the breakage of the cell wall matrix of wheat bran, promoted the complete deconstruction of amorphous cellulose and the partial deconstruction of crystalline cellulose in wheat bran ultrafine powder, broke the intramolecular glycosidic bonds of cellulose and hemicellulose in wheat bran ultrafine powder, led to enhanced hydrogen bonding, and improved the quality characteristics of wheat bran ultrafine powder and the tensile properties of whole wheat flour dough. Therefore, ultrafine grinding combined with moderate glutenin holds great application potential as an important technical means for wheat bran modification.

Key words: wheat bran; quality characteristics; ultrafine grinding; glutenin