| With soybean protein isolated (SPI) and dextran as the main raw material, Soy proteinisolate-dextran conjugates was prepared via the initial stage of the Maillard reaction inmacromolecular crowding conditions. The physical and chemical prope rties, the function andstructure of the conjugates were studied. The aim was to further study the mechanism and thefunctional properties of the prod uct produced via Maillard reaction in macromolecularcrowding conditions. We hoped to get the large-scale production methods for meeting thefood industry desire and provide theoretical and technical basis for ind ustrial prod uction.1, The covalent attachment of dextran to protein was confirmed by sodium dodecylsulfate-polyacrylamide gel electrop horesis. The PAS staining proved it to be covalentconjugates. In macromolecular crowding conditions, reactant ratio1:1,6℃0for30h wasexcellent reaction conditions. High performance liquid chromatography showed that thecovalent conjugates molecular weight distribution a broader, molecular weight was abo ut1309kDa.2, After the cova lent attachment of polysaccharide, the functional characteristics andmolecular structure features of product were analyzed by circular dichroism spectrum,fluorescence spectra and differential thermal scanning calorimeter. The study found that thefunctional properties, thermal stability of graft product improvement, hydrophobic indexlower, and it was helpful for the improvement of product emulsification. DPPH free radicalscavenging capacity is relatively weak. Thermal analysis showed that the thermal stability ofthe product improved.Amino acid analysis results showed that the main sites of SPI anddextran Maillard reaction have lysine, arginine, homocysteine, leucine and phenylalanine,among them with lysine and arginine primarily. Circular dichroism spectrum showed that dueto the covalent binding modes into the dextran molecules, the protein secondary, tertiarystructure changes, the structure of the increased flexibility, alpha helix content decrease, betafolding and no rules curly content increased. Fluorescence spectrum analysis shows that thegrafted products in abo ut400nm with the largest fluorescence intensity. Dextran cancovalently bond to aromatic amino acids, which reduced the hydrop hob ic groups of surface of the proteins, and reduce the protein gathered together.3, In macromolecular crowding conditions, the Maillard reaction and enzymatic werecombined for the proteins glycosyl reaction, the enzymatic can greatly shorten the chemicalmodification reaction time. The grafted degree of Maillard reaction product between soyhydrogent protein and dextran was38.05%. The solubility, thermal stability, oxidationresistance and emulsification were analyzed to show the soy hydrogent protein-dextranconjugates had superior function, especially the oxidation resistance and emulsification, butits solubility are relatively poor. |
