Abstract:In this experiment，wheat bran was used as raw material，and extrusion treatment was carried out under die pressure of 1.3 MPa-1.6 MPa separately.Effects of extrusion pressure on the physical and chemical properties，microstructure and processing characteristics of wheat bran flour were studied.The results revealed that with the increase of the treatment intensity，the content of soluble dietary fiber in wheat bran increased，while that of phytic acid decreased，showing gradually obvious Maillard reaction.Broken wheat bran flour particle and smaller particle size due to the extrusion were observed in the microscopic investigation.Furthermore，with the increase of extrusion strength，the bulk density，tap density and relative weight gain of wheat bran flour were elevated，and the fluidity，hydration characteristics，thermal stability and antioxidant ability were significantly enhanced（P＜0.05）.From the current experimental results，the wheat bran flour after extrusion processing can be used as a high-dietary fiber food ingredient，and the experimental data provide reference for the automatic parameter setting of extrusion.