THE CONVERSION OF PROCYANIDINS AND PRODELPHINIDINS TO CYANIDIN AND DELPHINIDIN

Article abstract of DOI:10.1016/S0031-9422(00)94533-3

The hydrolysis of proanthocyanidins to anthocyanidins in n-BuOH-HCl (95:5) has been shown to be an autoxidation, the yield of anthocyanidin being critically dependent on trace metal-ion impurities.Reproducible yields of anthocyanidin may be achieved if iron(III) salts are added to the reaction medium, and a standard method of analysis of proanthocyanidins besed on use of an n-BuOH-HCl-Fe^III mixture is given.The ratio of absorbance maxima of the cyanidin (550 nm) produced to near 280 nm for the original procyanidin polymer solution was ca. 3.5. Key Word Index - Procyanidin; prodelphinidin; anthocyanidin; hydrolysis; autoxidation; iron salts; analytical method.