Study On The Properties And Applications Of Pre-gelatinized Wheat Flour

wheat flour and peeled wheat as used as raw material to get Pre-gelatinizedwheat flour(P-g WF) of different gelatinization degree, respectively by steamheating and air puffing; and ultra-structure, pastingproperties, thermodynamicproperties,retrogradation properties and resolve quality of P-g WF of differentgelatinization degree were investigated; the dough rheological properties of breadflour added different proportions P-g WF were studied; the optimum amounts ofP-g WF added into bread flour was determined by the experiment of bread baking.By using glucose glucoamylase to detect gelatinization degree, thegelatinization time of sample was20min,the dosage of enzyme was5ml,2%(m/v).The degree of gelatinization increased with steam heating time andshowed "S" shap.When the steam heating time were21min、25min、31min and60min,it got P-g WF respectively with gelatinization degree of39.39%、54.12%、66.27%and89.08%.When the pressure of steam was between0.6MPa to0.8MPa,the gelatinization degree of Pre-gelatinized wheat flour was increased with therising puffing pressure. When the puffing pressure were0.6MPa、0.7MPa、0.8MPand0.9MP, it got P-g WF with gelatinization degree of46.84%、80.79%、98.68%and99.57%.The relationship between physicochemical properties and gelatinization degreechanged with the preparation of P-g WF.The starch grain of steamed P-g WFappeared “hard agglomeration”, and the higher the gelatinization degree is, thehigher the "hard agglomerates” degree is; while the starch grains of puffing P-gWF occurred "soft reunion”, and the higher the gelatinization degree is, the higherthe "soft agglomerates” degree is. The curve of RAV of Pre-gelatinized wheat flourappears a raised gel peak during10min and11min,and the higher the gelatinizationdegree is, the larger the gel peak area is, and the sooner the peak appears; duringthe puffing P-g WF didn’t appear the phenomenon of "shear-thinning”; on thecontrary, the viscosity of the wheat flour paste occurs a slight increase in insulation stirring. When the gelatinization degree of P-g WF were54.12%(steamed) and46.86%(puffing), their Comprehensive reconstitution ware best. Thephysicochemical properties of both P-g WF(Steamed and puffing) have thefollowing common features: the higher degree the P-g WF gelatinization degree is,the higher initial gelatinization temperature is, the lower gelatinization enthalpy is,the smaller settlement of the plot is, the bigger water absorption index and thegreater the enzymatic is.The recological experiments of adding different proportions of puffing P-g WF(the degree of gelatinization is99.57%)into wheat flour indicated: the rheologicalproperties change significantly when add Pre-gelatinized wheat flour to wheat floursamples. The more addition amount of pre-gelatinized wheat flour to wheat flour,the more water absorption, the shorter dough development time and settlingtime,the greater weakening degree, the smaller extension area and tensileresistance of the dough.Adding steamed P-g WF(the degree of gelatinization is99.57%) into wheatflour and making bread,the result showed: the addition amount of steamed P-g WFwas4%，the specific volume of bread was the biggest, the aging regenerative ofbread was the lowest; when the addition amount was2%, the higher sensory scoresof bread was the highest, Considering both of the bread sensory score and theinhibition of the regenerative effect, the optimal additive amount of Pre-gelatinizedwheat flour to bread is2%to4%.