Method for enriching and purifying purple sweet potato pigment by macroporous resin

The invention provides a method for enriching and purifying a purple sweet potato pigment by macroporous resin. The purified red pigment of a purple sweet potato is obtained by performing resin column chromatography, elution, eluent collection, concentration and drying on a purple sweet potato extract by a non-polar porous absorption resin method. The process method comprises the following steps of: diluting the purple sweet potato extract in a proper proportion by taking the merchant non-polar macroporous resin as a carrier, directly performing macroporous resin column chromatography, after saturation adsorption, repeatedly washing and purifying by using 0.1 percent hydrochloric acid-aqueous solution until the eluent is colorless, eluting by using 30 percent acidified ethanol (containing 0.1 percent hydrochloric acid), performing the macroporous resin column chromatography again according to the dilution ratio of 1:6, and eluting by using 0.1 percent ethanol hydrochloride to obtain the high-purity enriched purple sweet potato pigment. The method for purifying the red pigment of the purple sweet potato is simple, convenient and rapid. The selected non-polar macroporous resin has the characteristics of high adsorption capacity and high desorption rate. In the method, the ethanol is taken as the solvent, and is low in cost and non-toxic. The method for purifying the red pigment of the purple sweet potato has the advantages of high treatment capacity, radical impurity removal, high pigment recovery rate, high reproducibility and reusable resin. The total content of the red pigment purified by the method is more than or equal to 89 percent, and the pigment yield is more than or equal to 94 percent.