Interaction Of Inulin With Starch And Protein And Its Effect On Dough

Noodles have always been the traditional food of the Chinese people.All kinds of refined flour are very popular,but excessive refinement will cause the loss of dietary fiber in flour products.There is growing evidence that inadequate dietary fiber intake can lead to a variety of chronic diseases.The usual method is to add cereal,legume or fruit and vegetable dietary fibers to refined flour.But most of these fibers are poor in water solubility,large in size and strong in rough feeling.Inulin will not affect the appearance,taste and quality of the final product,but also meet the intake needs of dietary fiber.This study analyzed the effects of inulin on the physicochemical properties of wheat starch and wheat gluten protein,which provided a theoretical basis for the application of inulin in flour products.The effect of different concentrations of inulin on gelatinization,textural,retrogradation and microstructural properties of wheat starch were evaluated by rapid visco-analyser,scanning electron microscope,texture profile analysis,X-ray diffraction,Fourier Transform infrared spectroscopy and low field-nuclear magnetic resonance.The addition of inulin increased the gelatinization temperature of starch and decreased the viscosity value during gelatinization.With regard to textural properties,inulin significantly reduced texture parameters such as starch gel hardness and cohesiveness.Recrystallization of amylose molecules was affected by low concentrations(less than 10%)of inulin,and starch retrogradation was restrained.The microstructure of wheat starch gel with inulin was denser and more uniform compared with that of wheat starch without inulin.The results suggest that inulin is effective ingredient in improving the qualities of wheat starch.The effects of inulin on emulsification and thermal properties of wheat gluten protein were studied by differential scanning calorimetry,Fourier Transform infrared spectroscopy.And the structure of wheat gluten protein was characterized by scanning electron microscopy.The results showed that the lower concentration of inulin had a greater effect on the emulsifying properties of wheat protein.Inulin can increase the denaturation temperature,decrease the enthalpy and increase the disulfide bond content.And the ?-turns structure of wheat protein transformed into ?-sheets structure and random coil structure in the presence of inulin.The gluten network structure was more dense with inulin addition.The analysis results of dough showed that the presence of inulin increased the gelatinization temperature of flour and simulated flour,and decreased the viscosity value.With the increase of inulin concentration,the weak bound water in the dough was converted to the tight bound water and the free water.At the same time,the combination degree of the weak bound water between the dough became stronger.Inulin improved the farinographical,textural and tensile properties of dough,and changed the color of dough.