Purification and Structural Analysis of Anthocyanins from Black Wolfberry and Mulberry

In order to study the effective method of the enrichment and purification of anthocyanin in black wolfberry and mulberry, and identify the structure of anthocyanin, the black wolfberry and mulberry extracts were purified by macroporous resins. The adsorption and desorption abilities of different types of the resins for anthocyanins were compared. LX-20SS was optimized as the resin for the purification of anthocyanins from black wolfberry. The purification conditions were as follows: The mass ratio of resin to crude anthocyanin powder of black wolfberry was at 10:1, and the elution concentration of ethanol was 70%, and the flow rate was 3 mL/min. After the purification, the content of anthocyanin reached 144.18±3.40 mg/g. DM-21 was optimized as the resin for the purification of mulberry anthocyanin. The purification conditions were as follows: The mass ratio of resin to crude anthocyanin powder of mulberry was at 20:3, and the elution concentration of ethanol was 30%, and the flow rate was 1 mL/min. The content of anthocyanin reached 112.44±2.24 mg/g after purification. High performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis for anthocyanin structures in black wolfberry and mulberry showed that the main anthocyanin in black wolfberry was petunidin-3-O-rutinose (p-coumaroyl)-5-O-glucoside, which accounted for more than 95% of the total anthocyanin. In addition, there are two main types of anthocyanins in mulberry, corresponding to cyanidin-3-glucoside and cyanidin-3-rutinoside, which accounted for 63.58% and 36.42% of the total anthocyanins respectively. The results provided references for the development of black wolfberry and mulberry.