Mechanism Study On Influence Of Chitosan On The Rheological Properties Of Wheat Dough

Chitosan was applied in the study of food,medicine and chemical industry because of its excellent properties,such as non-toxicity,biocompatibility,biodegraded,etc.Even has been proved that it has the biological functions like reduce fat,reduce cholesterol and improve immune function,etc.But because of chitosan only soluble in acid medium,insoluble in water,so the propertity restricts its application.In this paper,we mainly study the effects of chitosan(0%、0.4%、0.8%、1.2%、1.6%)and Vc-CTS mixed solution on the rheological properties and structural properties of the medium gluten wheat.the effect and mechanism were studied to provide a theoretical basis for the application of chitosan.The effect of adding Chitosan on the properties of dough showed that the wet gluten content,dry gluten content and water holding rate of dough increased with the increase of chitosan,and the gluten index decreased.The results showed that the formation time and stability time of dough increased with the increase of the amount of chitosan,which showed that the resistance to agitation of dough had a good improvement effect.The stretch curve area,tensile resistance and maximum tensile resistance of dough increase gradually in the range of chitosan addition 0~0.8%,and the elongation gradually decreases,indicating that the tensile properties of dough are improved,but the continuous addition will greatly reduce the tensile properties of dough.The results of texture and dynamic rheometer showed that chitosan could improve the viscoelasticity,chewiness and hardness of dough.Electron microscope observation showed that chitosan was embedded in gluten,and when the dosage was more than 1.2%,obvious structural collapse occurred.The content of the sulfhydryl group and the two grade structure of the dough showed that the content of the sulfhydryl group had no significant change,and the alpha helix in the two grade structure was slightly increased,indicating that the elastic structure in the dough increased slightly.Low field nuclear magnetic resonance experiments showed that the tightly bound water content in dough increased.Therefore,it is believed that adding chitosan alone can affect the microstructure of the dough by physical inlay,and the rheological properties of the dough are influenced by its own water absorption.In the study of the properties of Vc-Chitosan solution with different concentrations,it was found that pH,electrical conductivity and viscosity increased with the increased of chitosan in the same Vc concentration.pH and ionic strength were the important factors of protein denaturation.The viscosity of the solution decreased with the increase of stirring time,and the reduction rate was negatively correlated with the concentration of chitosan,indicating that the different chitosan concentration would lead to a certain difference in the degradation rate of the molecules in the solution.The effects of adding different concentration of Vc-CTS mixture on dough properties showed that the wet gluten content and gluten index of dough gradually increased with the increase of mixture concentration,indicating that the structure of the gluten was more stable.The stability time of the dough,the area of the tensile curve,the tensile resistance and the maximum tensile resistance increased significantly with the increase of the concentration of the mixture,which showed that the mixture and the tensile properties of the mixture were improved.The results of electron microscopy showed that the structure of the gluten network was more compact.The results of Fourier transform infrared spectroscopy found that the alpha helix increased significantly in the two stage structure of the gluten,and the content of free sulfhydryl group decreased significantly.It was proved that the Vc-CTS solution had an improved effect on the formation of the gluten.It is considered that there is a complex interaction between chitosan and gluten protein.