Formation of Decarboxylated Betacyanins in Heated Purified Betacyanin Fractions from Red Beet Root(Beta vulgaris L.) Monitored by LC-MS/MS

摘要

Mixtures of mono-,bi-,and tridecarboxylated betacyanins together with their corresponding neobetacyanins obtained from Beta vulgaris L.root juice as heating degradation products of betacyanins were identified by high-performance liquid chromatography with tandem mass spec-trometry(LC-MS/MS)and diode-array(LC-DAD)detection.Two monodecarboxy-betacyanin pairs of diastereomers were detected after the decarboxylation in ethanolic and aqueous solutions.Generation of 17-decarboxy-betacyanins and 2-decarboxy-betacyanins was suggested,the latter so far never having been attributed to betacyanin thermal degradation products.Other main products of decarboxylation were 2,17-bidecarboxybetanin,its isoform,and 14,15-dehydrogenated(neobeta-cyanin)derivatives of all the decarboxylated betacyanins.The results of this research are crucial in determining betacyanin degradation mechanisms in juices or extracts of B.vulgaris L.roots and other products containing these pigments.