Emulsion Stabilizing Properties of Soy Protein Isolates Mixed with Sodium Caseinates

Abstract

To most effectively utilize the valuable functional properties of soy protein isolates (SPI), it is necessary to study their functional behavior in complex systems where interaction with other components (e.g., proteins, fats, carbohydrates, etc.) is expected to occur. The effect of mixing SPI and sodium caseinates (SC) on SPI emulsion stabilizing properties (ESP) was evaluated by determining emulsion stability, % adsorption of proteins onto the oil globule surface and SDS-polyacrylamide gel electrophoretic analysis. In emulsions prepared using the shearing force method, the high ESP (77%) of SPI was decreased to a low level (15%)–the same as that for SC–by mixing SC with the SPI. The main reason for this phenomenon is the initial coating of the oil globules with a thin layer of SC which prevents adsorption of SPI.