Effects Of Bran Treatment And Kneading Process On Whole Wheat Dough And Bread

Whole wheat food embraces several benefits in terms of regulating intestinal flora,losing weight,fighting cancer and preventing cardiovascular diseases.However,it has low acceptance among consumers due to the poor sensory properties and processing characteristics.This paper will focus on improving the quality of whole wheat dough and bread by changing the bran particle size,heating treatment of bran and applying a new kneading method.The main results of this study are as follows:Firstly,the bran with different particle sizes(unground,20 mesh,40 mesh,60 mesh,80mesh)was added back to the flour to study the effects of particle size of bran on wheat dough.The results exhibited that as the particle size decreased,the stability time rose.Stability time of dough with bran of 40 mesh was the highest,which was 1.23 times of that of unground.Both the area under the extensigraph curve and maximum resistance to extension rose and up to the highest when the bran could pass through 60 mesh sieves.Hardness,gumminess and chewiness of whole wheat dough reduced and cohesiveness rose.When the bran particle size was 60 mesh,the quality of dough was best and its hardness,gumminess and chewiness decreased by 25.12%,14.02%and 12.93%respectively and the cohesiveness increased by 14.70%.In conclusion,bran with a particle size of 60 mesh has the best improvement effect on the quality of whole wheat dough.Secondly,wheat bran with particle size of 60 mesh was treated by microwave,roasting,atmospheric steam and high-pressure steam respectively and the effects were compared.As the results displayed,compared with untreated whole wheat flour,atmospheric steaming and high-pressure steaming increased the stability time by 4.2 min and 2.5 min respectively.Compared with untreated whole wheat dough,roasting,atmospheric steaming and high-pressure steaming decreased the hardness of whole wheat dough by 16.11%,15.88%and 8.37%respectively.Atmospheric steaming and high-pressure steaming increased the springiness of whole wheat dough by 1.56%and 2.34%respectively.As for secondary structures of protein,roasting shrank the content of random structures and stepped up the content of?-turn.Atmospheric steaming and high-pressure steaming shrank the content of?-sheet while stepped up the content of?-turn.Microwave,roasting,atmospheric steaming and high-pressure steaming decreased the content of free sulfhydryl by 15.03%,34.57%,40.43%and 42.77%respectively,and increased the content of disulfide bond by 12.13%,30.15%,51.35%and 38.63%respectively.In conclusion,atmospheric steaming has the best improvement effect on the quality of whole wheat dough.Thirdly,bran of 60 mesh treated by atmospheric steam was added to flour,and when to add bran was researched.As the results displayed,compared with 0 min,with the delaying addition of bran,the ratio of bounded water rose first and then reduced while the ratio of immobilized water went down first and then stepped up.When adding bran in 4 min,the ratio of bounded water up to the highest and the ratio of immobilized water went down to the lowest.G'and G"first increased and then decreased.When adding bran in 4 min,the G'and G"up to the maximum.Hardness,gumminess and chewiness of whole wheat dough first reduced and then rose,when adding bran in 4 min,hardness,gumminess and chewiness decreased 16.80%,17.09%and 18.26%respectively and the dough had the best quality.In conclusion,adding bran in 4 min can best improve the quality of whole wheat dough.Finally,the whole wheat dough improved by the three methods as above was made into bread and the results proved that the quality was significantly improved.Compared with the whole wheat bread without improvement,the specific volume rose from 2.94 m L/g to 3.43m L/g;hardness,gumminess and chewiness decreased by 27.18%,24.56%and 23.53%,cohesiveness and resilience increased by 3.59%and 10.79%respectively;the average area of pore went down from 0.82mm~2 to 0.44mm~2,the porosity went down from 41.19%to 32.93%and the density of pore went up from 50.06/cm~2 to 75.45/cm~2;the sensory score went up from54.8 to 72.9.