Preparation of water-in-oil-in-water emulsions by low frequency ultrasound using skim milk and sunflower oil

Abstract

Double emulsions of water-in-oil-in-water (W1/O/W2) type were prepared in skim milk using 20 kHz ultrasound. Ultrasonic emulsification provides a simple and quick yet effective protocol by which double emulsions can be created using low amounts of surfactant. The fat displacement and shelf stability of the emulsions were found to be dependent on the amount of sonication power delivered during the dispersion of the W1/O emulsion into skim milk. Acoustic intensity was manipulated to control the size distribution of the outer shell of the emulsion droplets to a range similar to that of fat globules in unhomogenized whole milk. The encapsulation yield (proportion of W1/O droplets subsequently en..