Isolation of High Purity Anthocyanin Monomers from Red Cabbage with Recycling Preparative Liquid Chromatography and Their Photostability.

Anthocyanins from red cabbage are of great importance for their applications in the food industry as natural colorants and their beneficial effects on human wellness as natural antioxidants. This study aimed to develop an effective method for the isolation of anthocyanins with the help of a combination of alternate recycling and direct recycling preparative liquid chromatography. Ten major components of anthocyanins from red cabbage were isolated and their structures were identified by HPLC-MS/MS. Meanwhile, the stability of the isolated anthocyanins under various light conditions was also investigated so as to provide data for their storage. In sum, the results showed that twin column recycling preparative chromatography is an effective method for the isolation of anthocyanin monomers with similar structures. Besides, the stability of various anthocyanins from red cabbage was related to the number of acylated groups and mainly affected by illumination.