Study On The Extrusion Modification And Application Of Wheat Bran In Flour Product

The optimum technical conditions of extrusion modification of bran dietary fiber adopting twin-screw extrusion technology with bran as raw material were determined. The effects of extrusion modification on functions of bran were investigated, as well as the effects on properties of dough, the quality and shelflife of steamed bread and bread. The main findings were as follows:1. An experiment design with three factors and three levels were utilized based on the single factor test according to Box-benhnken using extrusion modification with bran as raw material. Response surface analysis(RSA) was used with soluble dietary fiber as response. The result indicated that the optimum condition were: moisture content 23%, expansion temperature 133℃,rotate speed 225r/min, content of bran dietary fiber 15.42%.2. After being squeezed, the main nutrients of bran changed. The content of soluble dietary fiber increased and that of insoluble dietary fiber and starch obviously decreased. The content of protein remained roughly the same. Water-solubility, foamability, water-holding capacity, oil-holding capacity, viscosity, acid resistance and liquidity of the bran promoted and the function improved.3. Modified bran had some effects on properties of dough. Water absorption of the dough increased and its extensibility decreased as the bran increased. Appropriately increasing bran could led to increasing formation time, stabilization time, promoting evaluation value, enhancing tensile resistance and tensile index and reducing weaken degree.4. Increasing bran appropriately could result to a better quality of steamed bread and bread, an increased volume of flour product and improvement of texture and shelflife of flour product. Under the experiment conditions, the addition of bran in steame bread was below 8% and that in bread was below 6%.