Emulsifying and Foaming Properties of Soy Protein Isolation with Covalent Modification by (-)- Epigallocatechin-3-gallate

摘要

Soy protein isolates (SPI) with covalent modification by (-)-Epigallocatechin-3-gaIlate (EGCG) were prepared under the alkaline condition. The effects of covalent modification on the emulsifying and foaming properties of SPI were evaluated. The Sodium dodecyl sulfate-poly aery lam ide gel electrophoresis (SDSPAGE) profiles of the modified SPI revealed that EGCG treatment caused cross-linking of subunits. Emulsifying activity of modified SPI significantly increased when compared with that of control (P< 0.05) at the concentration of 35 mg/ml. Modification of SPI by EGCG caused a decrease in the foam volume initially. In the range of 15 mg/ml to 35 mg/ml, the foaming activities of modified SPI were found to be less than those of the control (P<0.05). The foaming stabilities of modified SPI were significantly higher when compared to those of control (P<0.05). The results obtained in this study indicated that the modification by EGCG resulted in the enhancement of emulsifying activity and foaming stability of SPI. This modification may serve as a promising approach for improving functional properties of SPI.