Abstract:
【Abstract】 Cochineal extract was filtrated by ultrafiltration membrane with different aperturs, and the effects of different ultrafiltration proceses were studied. The optimum ultrafiltration process was determined as follows:after adjusting crude extracting solution of cochineal dye at pH 4, standing for 24 h, and then filtrating the supernatant by the spiral-renewable cellulose membrane with molecular weight cut-off of 5000. By this process 73% cochineal protein can be removed out of the cochineal extract, the purity of cochineal dye is increased, and the content of carminic acid reaches 54%.

Key words: cochineal dye, ultrafiltration membrane, refinement