Purification of Natural Food Colourants Using Membrane Technology - A Review

Membrane processing, in recent years, has turned out to be a useful unit operation for concentration of thermally labile food components. Concentration of natural colours has been one of the most novel applications of such technology especially when the colourants extracted from the natural sources are present in very low concentration. This review discusses some of the studies carried out on purification and concentration of natural food colourants from crude extracts using ultrafiltration (UF) and reverse osmosis (RO).