Optimized Preparation And Study Of Formation Mechanism For Soy Protein Isolate-fat Plural Gel

Soybean is one of the most important food crops in China.Soybean products occupy the position play a decisive role in the food industry.The protein and fat as the main two kinds of components in soybean products,the interaction between them has great influence on the food texture and structural characteristics.In recent years,the reports about soy protein isolate-fat plural gel are rare both here and abroad.So,in this study,the gel properties and structural properties were researched and analyzed by the methods of texture analysis,chromatism analysis,thermomechanical analysis,IR spectrum,scanning electron microscope and so on.The main results are as follows:1.In this study,the pre-emulsion soy fat were added to the mixed solution of soy protein isolate as the base material,and then the soy protein isolate-fat plural gel were made.The impact factors were determined by single-factor test,such as protein to fat ratio,heating temperature,heating time,p H and ionic concentration.The main factors influencing of different protein to fat ratio,heating temperature,heating time of plural gel were optimized with response surface methodology in this research.The texture properties of plural gel which were made under different conditions,such as gel hardness,springiness,cohesiveness and gumminess,have been tested and researched by the texture analyzer in order to set up the regression model.The optimum preparation conditions are deremined as follow: PFR 3.48,heating temperature 93 ?,heating time 40 min.2.Texture characteristics,water binding capacity,thermodynamic properties and chromatic aberration of soy protein isolate-fat plural gel were tested and analyzed by means of the changes of soy oil amount,in order to study the effects of interaction between soy fat and soy protein for the gel property of soy protein isolate-fat plural gel.The results show that,with the increasing of addition amount of soy oil,the probability of protein molecular aggregation in plural gel system were increased by the synergistic effect of soybean protein and fat,and the gel's hardness was increased,the gel's springiness,cohesiveness and gumminess were decreased first and then increased.Water holding capacity of gel was increased a little.The existing state of water in plural was changed.The values of L*,a*,b* were increased and the color of plural gel were showing lighter,greenish,yellowish.3.The disulfide bond content,IR spectrum,and scanning electron microscope of soy protein isolate-fat plural gel were tested and analyzed by means of the changes of soy oil amount,in order to study the effects of interaction between soy fat and soy protein for the structural property of soy protein isolate-fat plural gel.The results show that,with the increasing of addition amount of soy oil,the disulfide bond contents were decreased first and then increased and The sulfhydryl contents were increased slowly.The structure of the protein was destroyed in plural gel,which leaded to hydrophobic groups expose but the numbers of alpha-helix and ?-sheet were increased.The microscopic structure of surface of fracture in plural was more smooth and uniform.The network structure became more even and compact.