Study On Relationships Between Soy Protein Molecular Composition And Functional Properties In The Micelles Extraction Process

Soy protein is rich and of high-quality, with good nutritional function and unique processing characteristics of the modern food industry, which has become an indispensable raw material. Reverse micelle solvents represent nanometer-sized aqueous droplets stabilized by surfactants inside the bulk organic solvents. Reverse micelle extraction is a new separation technique suitable for macromolecular and purification, and has broad application prospect in the extraction of biological active substances. The reverse micelle system is similar to the living environment.In this paper, the reverse micelle system is used to soy protein extraction. It studied how to control W0 in AOT reverse micelle system and it also studied extracted soy protein’s functional properties and structural characteristics which is extracted by using the foreward extraction of soy protein and backward extraction process of soy protein extraction with AOT reverse micelles. It studied the extraction process of soy 7s, 11 s extraction.It studied how to control W0 in AOT reverse micelles. Studies have shown that with the increasing amount of water, W0 value increases in the reverse micelles, but as the ionic strength increases,W0 value decreases, and with the increasing concentration of AOT, the amount of water solubilization increase significantly of reverse micelles. By controlling the amount of water, ionic strength and AOT concentrations, the W0 value in reverse micelles can be controled effectively.It studied the foreward extraction and backward extraction process of soy protein extracted by using AOT reverse micelle system. Studies have shown that the optimum conditions of foreward extraction were: temperature 45℃, KCl concentration 0.05 mol/L, pH6.5, reverse micelle concentration 0.07 g/mL, extraction time 20 min, W0 15 and the optimum conditions of foreward extraction were: temperature 45 ℃, pH 8.5.ionic strength 1 mol/L,extraction time 40 min.It studied the two kinds of soy protein extracted by using AOT reverse micelle system and Alkali soluble acid sinking method. Studies have shown that the Solubility, Foaming and Emulsification of Soy protein which is extracted by reverse micelle are better than the traditionally extracted one. There is a lower percentage of disordered structure and β-fold.The studies of amino acid sequence in two kinds of soy protein have shown that the reverse micelle system makes the Amino acid sequence of soy 11S- A part and 7S- β part changed. In the soy protein extracted by using AOT reverse micelle system, the content of polar aminoacid increases and polar amino acid that is hydrophilic amino acid, has better solubility, which is a prerequisite for the function and properties of protein gel, foamability and emulsibility.such difference in Amino acids have an effect on the properties of soy protein.By using AOT reverse micelle system in the soy 7S, 11 S extraction, the optimum conditions of the extraction of soy 7S globulin are got. It studied the rheological properties of soy 7S, 11 S extracted in two methods. Studies have shown that the apparent viscosity of reverse micelle extracted soy 7S, 11 S is lower than the traditionally extracted ones. Extracted by reverse micelle,the content of 7S globulin increases relatively, and 11 S globulin decreases.The emulsion hydrophobic interaction in the gel and the role of disulfide bond increase, but as soon as the covalent bond effect less, its water-holding capacity lower. The EAI elevated and the emulsification of soy protein. The changes of relative globulin content in soy 7S and11 S lead to the difference of properties of soy protein.