Effect of reverse micelle on physicochemical properties of soybean 7S globulins

In this paper, the structural, thermodynamic, and rheological properties of soybean 7S globulins extracted by bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT)/isooctane reverse micelle method and alkali extraction-acid precipitation method were studied. Amino acid composition results showed that the 7S globulin produced by reverse micelle had more hydrophobic and sulfur-containing amino acids. Fourier transform infrared spectroscopy results demonstrated that the 7S globulin extracted by reverse micelle had more β-sheets but less turn structure, and formed a more compact conformation. However, lower surface hydrophobicity was observed in the 7S globulin extracted by reverse micelle, indicating that the reverse micelle environment could protect the native folded structure of protein. Thermal stability tests showed that the 7S globulin extracted by reverse micelle had poorer thermostability with lower denaturation temperature, which was in accordance with the results of initial gelling temperature. Final storage modulus (G’) and frequency sweep results revealed that the 7S globulin obtained by reverse micelle produced a harder textured gel.