Study On The Influence Mechanism Of Dough Making Process On Wheat Dough Characteristics And Gluten Network Structure

In the production of flour products,it is necessary to form a good gluten structure to give the products unique sensory and texture.In our study,the effects of vacuum blending,resting,calendering and additives on dough characteristics and gluten network formation were studied.Texture analysis(TPA),Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and laser confocal microscopy(CLSM)were used to study dough texture,protein structure and gluten network microstructure,and the underlying mechanism was explored.The main research contents include the following aspects:(1)The effect of vacuum blending technology on the dough characteristics and the network structure of gluten was studied.The distribution of water,tensile properties,protein properties and the formation of gluten network in the dough were compared under the two kinds of blending method for vacuum(0.06 MPa)and atmospheric pressure(0 MPa).The results show that increasing the amount of water added to dough could increase the content of frozen water and non-frozen water in dough,and the strong combined water was easier to migrate to weak bound water,and the dough has better extensibility.When the water content of the dough was 40% in vacuum blending,the content of sulfhydryl group is the lowest,the cross-linking degree of protein molecules was the highest,the content of ?-helix and ?-fold of protein secondary structure was the highest,and the gluten protein had a good order.Vacuum blending is beneficial to the formation of insoluble gluten macropolymers(GMP)and increase of the content of macromolecular weight polymer protein.(2)The effect of dough resting and aging forming on the dough characteristics and the network structure of gluten was studied.Two methods of ultrasonic dough resting(200 W)and ordinary dough resting(0 W)were used to compare the changes of texture characteristic,protein properties and the formation of gluten network under different resting time.The results showed that prolonged the resting time could improve the extensibility of dough,facilitate the formation of insoluble gluten macroaggregates,and increase the content of hydrogen bonds in dough proteins.The ultrasonic resting dough can improve the extensibility and viscosity of dough,depolymerize the insoluble gluten macropolymers,promote the transformation of sulfhydryl groups into disulfide bonds,and increase the content of macromolecular polymerins.Besides,by affecting the intermolecular force of protein,the ultrasonic resting dough could increase the hydrogen bond content,reduce hydrophobic effect,and promote the formation of ?-sheets conformations.Besides,the gluten network was more tightly wrapped in starch after 10 min of ultrasonic resting,and the structure of gluten network was weakened after 20 min of ultrasonic resting,which had adverse effects on content and structure of gluten proteins.(3)The effect of calendering process on nonlinear deformation of dough and the network structure of gluten was studied.The dough sheets are rolled by eight different calendering methods,including the folding way,rotation angle,and calendering times.The results showed that the folding times could reduce the hardness of dough,promote the transformation of sulfhydryl group into disulfide bond,increase the content of GMP,and facilitate the formation of hydrogen bond.Rotation of 90° calendering significantly affected the transverse tensile properties,reducesed the content of sulfhydryl group,and was beneficial to the formation of protein macropolymers.When the calendering times were 10 times,the content of sulfhydryl group and hydrophobic interaction were the lowest.However the content of ?-folding and ?-helix,and hydrogen bond were the highest.(4)The effect of additives(salt and L-cysteine hydrochloride)on the dough characteristics and the network structure of gluten was studied.The results showed that salt could enhance the tensile strength of dough,facilitate the oxidation of sulfhydryl groups to disulfide bonds,promote the formation of GMP by protein cross-linking,and increase the content of ?-sheets conformation.When salt content was 2%,the gluten network of dough was formed best,and the coating of starch granules was the most compact.L-cysteine hydrochloride reduced the tensile properties of dough,cut off the disulfide bond in the GMP,increased the content of sulfhydryl groups,caused the depolymerization of protein polymers,increased the disordered structure of protein secondary,weakened the gluten properties,broke the gluten network,and gradually dissociated starch molecules.