Effect Of Wheat Bran Dietary Fiber On Protein Characteristics And Quality Of Chinese Steamed Bun During Fermentation

In recent years,with people's attention to the health properties of food,the concept of whole grain has gradually gained more attention.As the main by-product of wheat processing,wheat bran is rich in dietary fiber,which has attracted extensive attention.As a traditional Chinese fermented food,Chinese steamed bun plays an important role in people's dietary structure and it could be a good way to increase the intake of dietary fiber,but the addition of wheat bran dietary fiber will affect the quality of Chinese steamed bun.Fermentation is an important process in the processing of Chinese steamed bun,so it is of great significance to study the effect of wheat bran dietary fiber on the fermentation process of Chinese steamed bun.Using flour and wheat bran dietary fiber as raw materials,this paper studied the effects of wheat bran dietary fiber on the protein properties,dough properties during the fermentation and quality of Chinese steamed bun.Firstly,the effects of wheat bran dietary fiber on the protein properties in the fermentation process of Chinese steamed bun were studied,and the changes of free sulfhydryl group content,glutenin macropolymer content,molecular weight distribution,secondary structure,particle size distribution,fluorescence characteristics and surface hydrophobicity were measured.The addition of wheat bran dietary fiber reduced the contents of glutenin macropolymer,larger polymeric proteins and smaller polymeric proteins,and the average size of gluten decreased gradually.With the progress of fermentation,the content of glutenin macropolymer increased.When the amount of wheat bran dietary fiber was 3% and 6%,the average size of gluten did not change significantly,and when adding amount was higher than 9%,the average size of gluten gradually increased.With the addition of wheat bran dietary fiber,the content of free sulfhydryl group decreased,the fluorescence spectrum of gluten solution showed a red shift,and the surface hydrophobicity first decreased and then increased.With the progress of fermentation,the more wheat bran dietary fiber was added,the sooner the content of free sulfhydryl group of the fermented dough increased to the highest,and the fermented dough with the added amount of 12% and 15% reached the maximum after 10 minutes of fermentation.The ?-turns content of wheat bran dietary fiber fermented dough decreased,and the fluorescence intensity of gluten decreased significantly.Secondly,the influence of wheat bran dietary fiber on the dough properties during the fermentation of Chinese steamed bun was studied,and the extensional properties,ferment rheology properties,dynamic rheological properties,texture properties and microstructure of the dough were measured.The addition of wheat bran dietary fiber reduced the extensibility and maximum resistance and the maximum dough fermentation height,and the time at which gas starts to escape from the dough(Tx)becomes shorter.The addition of wheat bran dietary fiber increased the elastic modulus and viscosity modulus of the dough,but both decreased significantly when the fermentation time was 10 min.The hardness and resilience of dough increased significantly with the increase of content of wheat bran dietary fiber,but both decreased with the progress of fermentation.The microstructure experiment also intuitively observed the destruction of gluten network by adding wheat bran dietary fiber during fermentation.Finally,the effect of wheat bran dietary fiber on the quality of Chinese steamed bun was studied,and the color,specific volume,texture,moisture distribution and microstructure of Chinese steamed bun were determined.With the increase of the wheat bran dietary fiber content,the specific volume of the Chinese steamed bun significantly decreased,the L* value of the Chinese steamed bun showed a noticeable downward trend,and a* value and b* value gradually increased.The hardness and adhesiveness of Chinese steamed bun first increased and then tended to be stable,the springiness and resilience first increased and then decreased,the cohesiveness decreased and the chewiness increased.The content of combined water in Chinese steamed bun increased and the content of bound water decreased.SEM results showed that with the increase of wheat bran dietary fiber,the pores in the Chinese steamed buns became small and dense.When the amount of wheat bran dietary fiber content was large(12%,15%),it was almost difficult to see the obvious air chamber structure.