600254 A method for the manufacture of an oil and water emulsion is disclosed. The method comprises passing a first emulsion through a microfluidisation device to form a second emulsion, thereby reducing the average oil droplet size, and then filtering the second emulsion. The microfluidisation device comprises an interaction chamber (as pictured in figure 4), which may be of Z-type geometry, connected in fluid communication with a back pressure chamber (not pictured), which is located downstream of the interaction chamber. The interaction chamber comprises a plurality of channels (32). When an input emulsion enters the interaction chamber it is split into a plurality of sub-streams, via the channels, and then recombined (at 31), thereby reducing the emulsions average oil droplet size. During the fluid flow through the interaction chamber the fluid pressure drops (from P1 to P2). The back pressure chamber is of a similar construction to the interaction chamber, comprising one or more channels. During the fluid flow through the back pressure chamber the average oil droplet size is further reduced and fluid pressure is also further dropped, wherein the rate of fluid pressure drop is decelerated. The slower fluid pressure decrease may lead to an increase in product stability because there is less gas enclosed in the emulsion. The further reduction of average oil droplet size through the back pressure chamber may also provide improved filtration performance, wherein less content is lost during filtration due to oil droplet size being smaller.
