Effects Of Different Starches On Qualities And Mechanisms Of High-moisture Tissue Peanut Protein

Starch has the function of improving food characteristics.Starch can be used as thickeners,reinforcers and binders to enhance the water retention of textured protein products,improve the taste and color,and stabilize the extrusion process and the properties of products.Under extrusion conditions,starch and peanut protein combine to form a complex food system.The interaction between different components in the system has an important impact on the structure and function of food.Peanut protein powder was used as the main raw material to study the effects of Cassava starch(CS),Acetyl distarch phosphate(ADSP)and Hydroxypropyl starch(HS)on the quality improvement and protein structure of high-moisture tissue peanut protein.The main conclusions were as following:1.Through Uniform Test and Partial Last Squares regression modeling analysis,the influence of extrusion parameters on extruder system parameters and product characteristics was studied.The results showed that the extrusion temperature and moisture content play an important role in improving the efficiency of extruder and the quality of textured protein products.Comprehensive considering the system parameters of the extruder and the characteristics of the protein products,the optimal extrusion process conditions are optimized:the extrusion temperature was 150?,the screw speed was 260 r·min^-1,the moisture content of material was 65%,the feeding rate was 9 kg·h^-1,and the cooling temperature was 45?.2.Peanut protein was blended with CS,ADSP and HS respectively to discuss the effects of CS,ADSP and HS on extrusion system parameters,product quality and protein structure characteristics under high moisture extrusion conditions.The results showed that the addition of starch reduced the SME and die pressure of the extruder;the addition of 3%ADSP and 6%HS respectively could significantly improve the degree of organization of the product.With the increase of the amount of starch,the hardness and chewiness of the product decreased significantly,but the lightness(L^*)value of the product increased significantly;NMR analysis showed that ADSP reduced the degree of freedom of water in textured peanut protein.HS promoted the transformation of free water in textured peanut protein to difficult flowing water,and the proportion of bound water of textured peanut protein added with CS was higher and its water holding capacity was stronger;FT-IR and SEM analysis showed that ADSP and HS promoted the transformation of protein secondary structure from random coils to?-sheets and the formation of protein network.Chemical crosslinking bond change showed that starch promoted the hydrophobic interaction between proteins,and the hydrophobic interaction and disulfide bond interaction were the main forces to form the fiber structure of textured peanut protein.SDS-PAGE,UV absorption,Fluorescence spectrum and DSC analysis showed that the interaction between starch and protein formed a high molecular weight polymer,aggregated into a three-dimensional network structure,promoted the transformation of small molecular weight protein subunits into large molecular weight protein subunits,and improved the order of protein structure.3.The effects of CS,ADSP and HS on the functional properties and digestive properties of textured peanut protein were studied.The results showed that the water and oil absorption capacity of textured peanut protein products added with ADSP and HS was enhanced.HS improved the water and oil absorption capacity of textured peanut protein most,which were 3.05 g/g and 1.17 g/g respectively.Compared with the textured peanut protein without starch,the textured peanut protein containing CS,ADSP and HS has better emulsifying performance and lower thawing loss.CS has a significant effect on the digestibility of textured peanut protein.