Purification of Anthocyanins with o-Dihydroxy Arrangement by Sorption in Cationic Resins Charged with Fe(III)

In the present work,a new purification method of anthocyanins with o-dihydroxy arrangement is proposed. this method is based on a ligand-exchange mechanism,using a cationic exchange resin loaded with metallic ions in order to increase the affinity of the resin to the anthocyanin(s) with o-dihydroxy arrangement. this method was used to purify the main anthocyanin (cyanidin-3- glucoside; cy-3-glc) from the anthocyanic methanolic extract of blue corn. the best sorption result was using fe(iii) in its ion form.the purification procedure begins with the formation of a metal-anthocyanin complex (cy-3-glc-fe) which was optimal at ph 5,followed by a naoh 0.1melution process in order to eliminate anthocyanins without o-dihydroxy arrangement,sugars,and organic acids. finally,the pure anthocyanin is obtained by adding hcl 0.1m which breaks the metal-anthocyanin complex. © 2014 araceli castañeda-ovando et al.