March 17/Campinas, Brazil/Engineering Business Journal -- "The effect of pH, addition of a thickening agent (locust bean gum) or high-pressure homogenization on the stability of oil-in-water emulsions added by sodium caseinate (Na-CN) was evaluated. For this purpose, emulsions were characterized by visual analysis, microstructure and theological measurements," scientists writing in the Journal of Food Engineering report.

"Most of the systems were not stable, showing phase separation a few minutes after emulsion preparation. However, creaming behavior was largely affected by the pH, homogenization pressure or locust bean gum (LBG) concentration. The most stable systems were obtained for emulsions homogenized at high pressure, containing an increased amount of LBG or with pH values close to the isoelectric point (pI) of sodium caseinate, which was attributed to the size reduction of the droplets, the higher viscosity of continuous phase and the emulsion gelation (elastic network formation), respectively. All the studied mechanisms were efficient to decrease the molecular mobility, which slowed down the phase separation of the emulsions," wrote F.A. Perrechil and colleagues, Campinas State University.

The researchers concluded, "In addition, the use of sodium caseinate was also essential to stabilize the emulsions, since it promoted the electrostatic repulsive interactions between droplets."

Perrechil and colleagues published their study in the Journal of Food Engineering (Oil-in-water Emulsions Stabilized by Sodium Caseinate: Influence of pH, High-pressure Homogenization and Locust Bean Gum Addition." Journal of Food Engineering, 2010;97(4):441-448).

Additional information can be obtained by contacting R.L. Cunha, Campinas State University, Dept. of Food Engn, Fac Food Engn, POB 6121, BR-13083862 Campinas, SP, Brazil.

From the March 29, 2010, Prepared Foods E-dition