The present invention relates to artificial oil bodies comprising oleosin (which, as presently defined, also encompasses caleosin, steroleosin and polyoleosin), a surfactant such as a phospholipid, and an oil comprising fatty acids, such as polyunsaturated fatty acids having four or more double bonds. The present invention also relates to methods of preparing said artificial oil bodies. These AOBs may further comprise other molecules such as bioactive molecules, used in a wide variety of products, and are particularly useful for producing oxidatively stable oil-in-water emulsions in the absence of added antioxidants. The present invention further encompasses a method for the partial purification of oleosin from a plant extract.