Preparation And Application Of Functional Wheat Bran

Wheat kernels are rich in bioactive components and micronutrients that are mainly present in the outer bran layers,especially aleurone layer.Debranning can partly remove the out bran layers such as outer pericarp and inner pericarp with high content of insoluble dietary fibres,and milling process can separate wheat bran components from endosperm.The functional wheat bran(FWB)with rich aleurone was prepared by technology of milling after debranning with optimum pearling rate,tempering condition and microwave stabilization parameters in this paper.The storage characteristics of FWB and the effect of wheat bran addition on dough rheology and steamed breads quality were investigated.The main findings are as follows:(1)Preparation technology of FWB.With the increase of the degree of debranning of wheat,the content of phytic acid and total phenol and the antioxidant activity in vitro of wheat kernels were increased at first and then decreased,and the highest value was reached when the pearling rate was 4%,while the content of ARs decreased gradually.The content of Phytic acid in wheat bran is higher when the pearled wheats(moisture content: 11%)was milled without tempering than that with tempering.Therefore,to prepare the FWB,the optimal pearling rate is 4% and the process of tempering is not needed.(2)Microwave treatment significantly improved the stability and antioxidant capacity in vitro of FWB(P<0.05).After comprehensive consideration of the physical and chemical characteristics and color changes of the FWB,the stabilization parameter was optimized to be microwave power of 7.5 k W,and the treatment was performed at 120 s: the moisture content of the FWB reduced from 11% to 3%,the lipase activity reduced from 24.4 mg/g to 12.0 mg/g,and the fat acidity reduced from 90 mg/100 g to 44 mg/100 g,the total phenol content in extraction solution increased from 1.21 mg/g to 1.66 mg/g,and the ability to scavenge DPPH and ABTS free radical increased to the highest value.During the accelerated storage test,the fat acidity of the stabilized FWB increased from 45 mg/100 g to 80 mg/100 g that meet the standards of edible wheat bran industry.(3)The addition of FWB has effects on the processing quality of wheat flour,including the properties of gluten,gelatinization,farinographical and tensile.With the increase of addition amount,the content of wet gluten and the water holding rate of gluten increased(P<0.05),the water absorption rate of flour,the dough forming time and the stabilization time were prolonged(P<0.05),and there is no significant change in softening degree and flour quality index(P>0.05).At the same time,the gluten index continued to decline,and the gelatinization and tensile properties decreased significantly(P<0.05).The addition of WB decreased the processing quality of wheat flour significantly(P<0.05).Compared with the WB,the addition of FWB can improve the processing quality of wheat flour by improving the gluten strength and dough stability to a certain extent.(4)Effect of FWB addition on steamed breads.The FWB was found to reduce steamed breads specific volume,springiness,cohesiveness and resilience and to increase height-diameter ratio,hardness,chewiness and adhesiveness.The higher the amount of addition,the more obvious the phenomenon.Color and sensory quality of it decline at the same time.The quality of steamed breads declined.When the content of wheat bran was higher than 6%,the height-diameter ratio,specific volume and color of FWB steamed breads were better than that of WB steamed breads.When the content of wheat bran added was higher than 12%,the texture characteristics of FWB steamed breads were better than that of WB steamed breads.The application of FWB in steamed breads is expected to improve the level of the nutritional intake of whole grains.