IMPROVED METHOD FOR THE STABILIZATION OF ANTHOCYANIDINS

Anthocyanidins, prepared by the acid hydrolysis of black bean and blac kberry anthocyanins, were deposited in C-18 solid-phase extraction (SP E) cartridges from four different manufacturers. The amount of the bla ck bean anthocyanidins, delphinidin, petunidin, and malvidin (monitore d at 520 nm) was unchanged for the first 7 days of storage in SPE cart ridges under nitrogen atmosphere at 2 degrees C. After 45 days of stor age the level of delphinidin, petunidin, and malvidin was reduced to 8 2, 63, and 49% of the original content, respectively. In contrast, the level of delphinidin, petunidin, and malvidin decreased to 17, 10, an d 3%, respectively, of the original amount when these anthocyanidins w ere stored for 3 days in acidic methanol (0.01% HCl) at 2 degrees C. S imilarly, after 46 days of storage in SPE cartridges under nitrogen at mosphere at 2 degrees C the amount of cyanidin (obtained from evergree n blackberry puree) decreased to 75% of the original content. Cyanidin almost completely disappeared (only 0.2% remained) when it was stored for 4 days in acidic methanol (0.01% HCl) at 2 degrees C. Anthocyanid in stability was markedly different depending on the brand of the SPE cartridge on which it was stored.