Study On Extrusion Process Of Fine Barn And Application Of Extruded Fine Barn

Using fine bran which was the by-product of wheat flour as raw material, twin-screw extrusion technology as method, the influence of extrusion process condition to fine bran extrusion characteristics was studied by using response surface method under the basement of single factor experiments. The effects of extrusion on functions of fine bran were investigated, as well as the effects on properties of dough and the quality and shelf life of bread. The main findings were as follows:1. Process parameters regression equations of extrusion technology of fine barn: Y=2.38+0.045X1+0.046X2+0.086X3+0.024X4-0.009375X1X2+0.012X1X3-0.013X1X4+0.053X2X3+0.011X2X4-0.021X3X4-0.14X12-0.14X22-0.14X32-0.10X422. The regression equation could make a good forecast of the expansion degree change rule under different extrusion process conditions. The optimal process condition were: material diameter at60mesh, material moisture at28.5%, extrusion temperature at144℃and screw speed at350r/min. And the fine bran expansion degree was2.39under this extrusion process condition.3. After extrusion treatment, the main nutritional components of the fine bran changed. The color became deeper, the content of fat, starch and insoluble dietary fiber decreased, soluble dietary fiber increased obviously, the content of protein and ash were little changed, the total phenolic content and DPPH-clearance rate increased. The WSI, WAI, expansibility and frothiness of fine bran increased, flow ability decreased, and the internal structure changed obviously. Functional properties of fine bran improved.4. Adding extruded fine bran had some influence on pasting properties and dough rheological characteristics of bread flour. As the increased of add quantity, the peak viscosity, peak viscosity, low viscosity, attenuation values, final viscosity, regenerative, peak values time of bread flour and the ductility of dough decreased, the pasting temperature, the water absorption and stretching ratio of dough increased. When the addition between0-4%, as the increased of add quantity, the formation time, stability time, index of farinograph properties, tensile energy, stretch resistance increased. When the add quantity beyond4%, they started to decrease obviously. It showed that adding extruded fine bran could improve the farinograph properties and tensile property of bread flour suitably.5. Adding extruded fine bran suitably could increase the moisture content and nutritional value of bread, extend the shelf life. In this experimental condition, the best add quantity of extruded fine barn was4%.