A blue color was formed after standing for 15 min in the light. After centrifugation and filtration with membrane filter, the blue and the natural pink pigments of the strawberries were separated using a Sep-pak Cl8 column. The column was first eluted with 50% aqueous methanol solution which removed the pink pigments, and then with pure methanol to remove the blue pigment. The concentration of the latter was determined by measuring its absorption at 565 nm and calculated from a calibration curve using K2S.