The influence of ultrasound on the stability of dairy-based, emulsifier-free emulsions: rheological and morphological aspect

This study has been designed to examine incorporation of 7, 10 and 15% olive oil in milk-based media by using ultrasound (US) at 24 kHz, for 3 min in order to form new dairy-based, emulsifier-free emulsions. The prepared emulsions were characterized in terms of the emulsion capacity and stability, creaming index, zeta potential, droplet size, color and rheological analysis. The morphology of the emulsions was examined under the fluorescence microscope to evaluate the changes caused by US. The peroxide value and fatty acid composition were determined. After the treatment, application of the US increased the stability of emulsions. A decrease in the creaming index and droplet size and an increase in the zeta potential were observed. All the emulsions exhibited a weak gel structure. The fluorescence microscope images showed that the US decreased the size of oil droplet.