Ultrasound assisted adsorption and desorption of blueberry anthocyanins using macroporous resins

In this study, the impact of ultrasound on the adsorption and desorption features of blueberry anthocyanins on macroporous resins were studied. Sonication was performed at 106-279 W/L and 20-30 °C in a pulsed mode, respectively. Generally, ultrasound treatments within the selected experimental range enhanced the adsorption/desorption process of anthocyanins on macroporous resins. The recovery of blueberry anthocyanins after ultrasound-assisted adsorption/desorption process at 279 W/L and 20 °C was 82.12%, which was 52.84% higher than that obtained after adsorption/desorption with shaking at 100 rpm. Meanwhile, higher acoustic energy density (AED) levels and lower temperatures benefited the adsorption process through enhancing the adsorption capacity and shortening the equilibrium time, whereas higher temperatures promoted the desorption process. Furthermore, malvidin-3-galactoside had the highest adsorption and desorption capacities among all the studied monomeric anthocyanins. No organic acids and sugars were detected after adsorption/desorption processes, indicating the successful improvement of anthocyanin purification. Sonication mainly enhanced the adsorption process by means of strengthening the formation of hydrogen bond on resins surface and increasing their surface roughness. Overall, ultrasound can be an effective tool to improve the purification of anthocyanins using macroporous resins.