ENCAPSULATION OF FISH OIL IN BIODEGRADABLE POLYMERS BY THE PGSS PROCESS

摘要

Fish oil contains high amounts of omega 3 fatty acids, which are used as food ingredients, due to their positive effects and health benefits on human beings. Especially for the prevention of cardiovascular diseases, omega 3 fatty acids are discussed. The use of fish oil in food- and pharmaceutical products is problematic, due to the low oxidation stability of the oil. This leads to a nasty smell or taste of the products. For this reason the improvement of the stability of the omega 3 fatty acids towards oxidation is one of the major tasks in food industry. A high pressure spray technique (PGSS = Particles from gas saturated solution) has been applied to encapsulate fish oil in a biodegradable polymer. As polymer Chitosan, which is a deacetylated derivate of chitin, was used. Chitosan is a Polysaccaride, a natural bioactive macromolecule, which is generally derived from crustacean shell waste. Conventional encapsulation techniques, such as spray drying, need relatively high temperatures, which can lead to oxidation of the oil already during processing. In the PGSS-drying process a supercritical fluid; in this case carbon dioxide, is dissolved in a liquid emulsion which consists of Chitosan, maltodextrin, fish oil, water and an emulsifier. The supercritical gas is contacted with the emulsion in a static mixer. Followed by a rapid depressurization of this emulsion through a nozzel. The water is already extracted by the gas in the static mixer, so that after expansion only a small amount of solvent has to be evaporated in the spray tower. The conditions in the spray tower have to be set in such a way, that condensation is avoided and products with low water residues are obtained and in addition a thermal deterioration of the fish oil is prevented. The particle size of the obtained particles was measured with a laser diffraction method using a Mastersizer 2000. The morphologies of the particles were analyzed by SEM (scanning electron microscope). The amount offish oil on the surface of the particles was determined by ultra violet spectrometer (UV). The humidity of the powder was analyzed by evaporating the water in an oven. The contribution will illustrate the PGSS process, which was used for the encapsulation, and will point out the influence of the main process parameters on particle size, particle morphology, residual humidity and oil content of the fish oil capsules.