High pressure homogenization (HPH) is a novel non-thermal preservation technology, which can improve the microbiological quality of products without affecting their stability. The main objective of this paper is to study the influence of different HPH treatments on the structure of a sauce (an egg/dairy emulsion). in order to obtain the higher physicochemical stability. The oil-in-water emulsion was stable up to 100 MPa with the oil droplets surrounded by several layers of natural emulsifiers. Critical pressures, between 150 and 250 MPa, produced a destabilization of the emulsion thus causing a separation of phases. A coalescence phenomenon progressively occurred when pressure increased. This phenomenon was due to the loss of the natural emulsifier barrier. Changes on the electrophoretic pattern were also observed at high pressure levels, showing an insolubilization of proteins. Lipid fraction was observed to be chemically stable after the HPH treatment. (C) 2011 Elsevier Ltd. All rights reserved.