Effect of environmental factors on the droplet size of o/w emulsion stabilised by beta-lactoglobulin.

The effect of environmental factors (protein concentration, pH, ionic strength) on emulsification properties of beta-lactoglobulin (beta-Lg) was analysed. The protein was obtained from phospholipoprotein-free whey 25-fold concentrated by ultrafiltration (10 kDa cut off) after precipitation of alpha-lactalbumin (alpha-La) with 6% trichloroacetic acid. The Sauter diameter D(vs) of oil droplets in the emulsion stabilised by beta-Lg was found to increase with increases in the protein concentration in the range of 0.5 to 2.0% and medium acidity in the pH range of 5.0 to 7.0. An increase in ionic strength in the range of 0 to 100 mM caused that the emulsification properties of the protein worsened as compared with control emulsion.