Preparation,Characterization And Application Of Composite Dietary Fiber

As two important nutrients in food system,dietary fiber and protein are essential components of many natural and processed food materials.In addition to its nutritional value,dietary fiber and protein also have many special functional properties,which are widely used in food processing to improve food quality.In this experiment,soybean dietary fiber(SDF)and soybean protein isolate(SPI)were used as raw materials to modify two different food components.In order to promote the interaction between dietary fiber and protein,composite dietary fiber was prepared by heat treatment and ultrasonic treatment.The structure of composite dietary fiber was characterized and its properties were determined,Finally,the application of soybean dietary fiber and soybean protein isolate in food was discussed in order to expand the application scope of soybean dietary fiber and soybean protein isolate in food.The main results are as follows:(1)By measuring the turbidity,apparent viscosity and fluorescence intensity of the soybean dietary fiber-soybean protein isolated complex system under different complex ratio,different heating temperature and different ultrasonic power treatment conditions,the compound degree of dietary fiber and protein under different treatment conditions was discussed.The results showed that when the complex ratio was 1:1,The compound degree of dietary fiber and protein was the best under 80℃ heat treatment and 300 W ultrasonic treatment.(2)The results of particle size,zeta potential and scanning electron microscope showed that the ultrasonic treatment significantly reduced the particle size,increased the electrostatic repulsion between particles,and improved the stability of the composite system.Heat treatment combined with ultrasonic treatment can further reduce the particle size of composite dietary fiber,the rough surface of dietary fiber is covered by protein molecules,the surface of composite particles is smooth,and the size and distribution of composite particles are more uniform.Fourier transform infrared spectroscopy and differential scanning calorimetry showed that there was no covalent interaction between dietary fiber and protein in the composite process,and there was a small amount of hydrogen bonding and weak electrostatic interaction between dietary fiber and protein.Heat treatment and ultrasonic treatment increased the number of hydrogen bonds between the composites and improved the stability of the composite particles in the process of thermal denaturation.After heat treatment combined with ultrasonic treatment,the thermal stability was further improved.(3)The results showed that the composite dietary fiber modified by heat treatment combined with ultrasonic treatment had the best modification effect and the lowest water holding capacity,but the oil holding capacity increased;The emulsifying property and emulsifying stability increased significantly;The foaming property and foaming stability were also improved,and the modified composite dietary fiber had better functional properties,which indicated that heat treatment combined with ultrasonic treatment had a synergistic effect on the modification effect of dietary fiber protein.(4)The sensory score of the composite dietary fiber pork balls with heat treatment combined with ultrasonic treatment was the highest.The improvement of color,reduction of cooking loss and change of texture further showed that the modified composite dietary fiber had better effect on improving product quality than SDF,SPI and untreated,and had higher practical application value.