Study on Extraction, Purification and Degradation Kinetics of Anthocyanins from Lycium ruthenicum

In this study, taking the amount of anthocyanin extraction as the main index, the extraction process of lyophilized Lycium ruthenicum anthocyanin was optimized by one-way and orthogonal tests, and the purification process of anthocyanin and its degradation kinetics were studied under these conditions, to explore the changes of the extraction amount of anthocyanin under different temperatures and pH. The results showed that the optimal conditions for the extraction process: The material-liquid ratio was 1:25 (g:mL), the ethanol concentration was 60%, the pH was 4, and the extraction time was 2 h, which resulted in a purification rate of 90.02%. The amount of anthocyanosides extracted under these conditions amounted to 36.507±0.325 mg/g. In addition, the study showed that AB-8 macroporous resin was the most effective in purifying anthocyanin from Lycium ruthenicum, and it had the best effect on the adsorption and desorption of anthocyanin. The optimal conditions were: The concentration of the sample solution was 200 mg/100 g, the concentration of desorbed ethanol was 80%, the flow rate of the sample was 2 mL/min, the flow rate of elution was 2 mL/min, and the volume of the sample was 5 BV. The results of the degradation kinetics study showed that the degradation rate of anthocyanin increased with increasing temperature and the half-life decreased at the same pH. Moreover, anthocyanosides were more stable in acidic environment and easily degraded in alkaline environment, and the stability of anthocyanosides was the best with the maximum of t_1/2 of 38.5 h and the maximum of Ea of 41.89 kJ/mol at pH3 and 50 ℃. Therefore, the content of Lycium ruthenicum anthocyanin is closely related to its extraction, purification and stability of process conditions, this study provides technical support for the extraction of wolfberry anthocyanin and the development of beverages.