Effects of Microwave and Ultrasound Treatment on the Grinding Characteristics of Wheat Bran and the Quality of Whole Wheat Dough

After treated by microwave and ultrasound, the wheat bran was ground and sieved into three parts, coarse (280~450 μm), medium (154~180 μm) and fine (≤71 μm). Then the texture properties, rheological properties and free sulfhydryl content of whole-wheat dough were investigated. The relative enzyme activity and particle size distribution of wheat bran showed that ultrasonic treatment and microwave treatment could better improve the stabilization effect and crushing efficiency, and the effect of ultrasonic treatment group was better (P<0.05). The dough quality showed that with the decreasing of wheat bran particle size, the hardness and stickiness of microwave treatment group decreased, and the cohesion increased. The hardness and adhesiveness of ultrasonic treatment group were lower than those of microwave treatment group (P<0.05). Rheological analysis indicated that the elastic modulus and viscous modulus of the microwave group decreased as the particle size of bran decreased, and were smaller than those of ultrasound-treated group the microwave-treated group at the same particle size. The free sulfhydryl content decreased gradually with the decreasing of bran particle size, and the decreasing of free sulfhydryl content was greater in the ultrasonic treatment (P<0.05). Microwave, ultrasonic treatment and the reduction of wheat bran particle size could effectively improve the quality of dough. In addition, the effect of ultrasonic treatment on dough quality was more significant than that of the microwave treatment group.