DISPLACEMENT OF NATIVE AND THIOLATED BETA-CASEIN FROM OIL-WATER INTERFACES - EFFECT OF HEATING, AGING AND OIL PHASE

Tetradecane- and soya oil-in-water emulsions stabilized by native and chemically thiolated p-casein were prepared using a microfluidizer. Di splacement of adsorbed protein by addition of the non-ionic detergent Tween 20 after 2 and 28 days storage at 20 degrees C, and before and a fter heating to 80 degrees C for 30 min, was determined colorimetrical ly. Adsorbed protein was displaced more readily from the 2-day-old tet radecane emulsion than from the soya oil. Heating reduced displacement from the soya oil emulsion, but not from the tetradecane. Thiolated p rotein was displaced less readily than native p-casein. storage decrea sed displacement of both forms of beta-casein from the soya oil emulsi ons and heating had very little effect on the stability of the adsorbe d protein in these aged emulsions.