Effect Of Debranning Degrees On The Quality Of Wheat Flour,Dough And Steamed Bread

The traditional milling process produces flour in a finely ground,multi-sieving manner,and its flour nutrients are lost.The first debranning and milling process retains the nutrient-rich aleurone layer and germ,which increases the nutrient content of the wheat flour.The debranning rate is an important indicator of the debranning and milling process.Studying the effect of debranning rate on wheat flour and its processing quality plays an important role in improving the milling technology.In this paper,the wheat grain was peeled off to different degrees,and the effect of debranning rate on the quality of wheat flour,dough and steamed bread was studied,which provided a theoretical basis for the application of wheat flour and its products.The research results of this topic are as follows:(1)With the increase of debranning rate,the content of ash,insoluble dietary fiber and total dietary fiber of wheat flour decreased,but they were significantly higher than refined flour;protein,soluble dietary fiber and damage starch content increased first and then decreased,the highest value was reached when the debranning rate was 6%;the falling value was increasing,the wet gluten and dry gluten content were not changed,and the gluten index was gradually increased;peak viscosity,trough viscosity,breakdown viscosity,final viscosity,setback were all increasing;the onset temperature,peak temperature,conclusion temperature all decreased.(2)With the increase of debranning rate,the water absorption rate of wheat flour and the breakdown viscosity of dough decreased gradually;there were no significant difference in the degree of weakening between dough of different debranning;the setback,cooking stability,resistance to extension,extensibility,extensibility area,extensibility rate showed an increasing trend;as the scanning frequency increased,the storage modulus and loss modulus of the dough increased throughout the linear viscoelastic region.As the debranning rate increased,the storage modulus and loss modulus of the dough showed a downward trend at the same frequency and the strain and recovery ability of the dough gradually increased at the same time;when the temperature was raised from 25 ~oC to 60 ~o C,the storage modulus of all the tested dough gradually decreased.The storage modulus of the dough decreased with the increase of the debranning rate at the same temperature.When the temperature was from65 ~oC to 90 ~oC,storage modulus showed an upward trend.Scanning electron microscopy showed that with the debranning rate increased,the free starch granules in the dough were reduced,and the arrangement of the starch granules and the gluten network was more uniform and dense.(3)With the increase of the debranning rate,the specific volume of the steamed bread increased,the L*value of the steamed bread core increased,the a*value and the b*value decreased,the elasticity,surface color,internal structure and viscosity of the steamed bread gradually improved,the sensory comprehensive score increased,hardness and gumminess gradually reduced,and cohesiveness and resilience gradually increased.When the debranning rate increased from 0%to 6%,the specific volume,brightness,sensory score and texture characteristics of the steamed bread varied greatly.When the debranning rate increased from 6%to 12%,the change of each index was smaller.For the steamed bread,the suitable debranning rate of Xi Nong 20 and Xi Nong 822 wheat is about 6%.With the prolongation of storage time,the hardness,gumminess and chewiness of steamed bread increased rapidly within 0~24 h,and increased slowly within 24~72 h,while cohesiveness and resilience decreased rapidly within 0~24 h and decreased slowly within 24~72h.