A New Xylitol Preparation Technology And Application In Flour Products

In this paper several extrusion technology in preparation of xylitol had carried onresearch in the application, had determined the optimal cob and acid extrusion puffed cobconditions of pretreatment, acid hydrolysis conditions, decoloring free method andfermentation process conditions. On this basis, the xylitol on dough properties and breadquality influence were studied and obtained the following main conclusions:(1) The regression equation of twin screw extrusion of corn cob with adding acid：Y=0.18+0.009125X1+0.01X2+0.016X3+0.003208X4-0.004188X1X2+0.003062X1X3-0.004313X1X4+0.011X2X3+0.001062X2X4-0.004437X3X4-0.02X12-0.025X22-0.028X32-0.008094X42The optimum processing twin screw extrusion conditions of corn cob with adding acidwere as follows：granularity60mesh, water content24%, hydrochloric acid concentration0.7mol/L, extrusion temperature120°C and screw speed300r/min. the xylitol yield under thiscondition was0.17g/g.(2) The regression equation of acid hydrolysis of the puffed corn cob:Y=0.33-0.003583X1-0.007167X2-0.027X3-0.002667X4+0.023X1X2-0.00675X1X3+X1X4+0.017X2X3-0.021X2X4+0.0075X3X4-0.049X12-0.04X22-0.016X32-0.065X42Optimum conditions of acid hydrolysis of puffed corn cob: material particle size50mesh,hydrolysis temperature100℃, concentration of hydrochloric acid0.6%, liquid ratio5mL/g,hydrolysis time60min. The xylose yield was0.37g/g and increased16.1%compared withthe traditional process.(3) Add acid extrusion of puffed corn cob hydrolyzate decoloration process parametersregression equations:Y=93.15-3.08X1+3.35X2+3.67X3-0.18X1X2-1.96X1X3+0.21X2X3-2.31X12-3.90X22-4.22X32Add acid extrusion puffed cob acid hydrolysate decolorizing optimum processparameters for: activated carbon particle size130mesh, the adding amount of2%, decoloringtemperature50℃and decoloring time40min.(4) The main impact factor of extrusion puffed corn cob hydrolysate fermentationpreparation xylitol was the fermentation temperature, followed by the fermentation time andinoculation quantity, liquid loading amount was less affected. The optimum process conditions of extrusion puffed corncob hydrolysate preparation ofxylitol fermentation were initial concentration of xylose is80g/l, inoculation quantity13%,fermentation temperature31℃, fermentation time96h and loading liquid ratio65%. In thisprocess conditions, xylose conversion rate was0.68g/g.(5)Xylitol could significantly improve the dough development time and stability time,decline water absorption. And xylitol had a positive connection with stretching energy,extension degree and stretching resistance when the addition between0~16%, and it woulddecline the properties after beyond16%. Add xylitol could significantly reduce the peakviscosity, the lowest flour viscosity, attenuation value, final viscosity and retrogradation valueand peak time, reduce the starch aging speed effectively.(6)Xylitol could improve bread baking characters, decrease the hardness, increase themoisture content, and extend the shelf life. Comprehensive analysis of the dough silty,stretching, gelatinization properties and bread baking characteristics and the shelf life of bread,determine the xylitol add quantity should under16%.