Physicochemical and antioxidant properties of hard white winter wheat (Triticum aestivm L.) bran superfine powder produced by eccentric vibratory milling

Hard white winter wheat (Triticum aestivm L.) bran was grinded by an eccentric vibratory mill below 30 ± 0.5 °C, and the effect of processing times (15, 20, 25 and 30 min) on the physicochemical and antioxidant properties of the superfine powder was investigated with disc-milled powder as control in the study. After vibratory milling treatment, the particle size of powder effectively reduced to a micron scale and the brightness increased, as well as the contents of soluble dietary fiber and phytic acid increased. Compared with the control, the eccentric vibratory milled bran powder showed higher values in bulk density (from 0.27 to 0.39 g/mL), tapped density (from 0.31 to 0.76 g/mL), water holding capacity (from 4.20 to 7.00 g/g), swelling capacity (from 1.67 to 2.87 g/g) and oil binding capacity (from 1.50 to 2.61 g/g), while lower values in angles of repose and slide in the processing time sequence. Meanwhile, the thermal stability was enhanced. And the decreases of IC₅₀ values for DPPH radical scavenging activity and ferrous ion-chelating activity suggested the improvement of antioxidant activity for bran superfine powder. The results indicated that the eccentric vibratory milled wheat bran superfine powder have various potential applications as food and pharmaceutical additives to improve the uniformity and/or to enhance functionalities of final products.