Study on Extraction and Purification Process of Anthocyanins from Blueberry Residue
The anthocyanins in blueberry residue are extracted by ultrasonic-assisted ethanol method.The optimal extraction conditions determined through orthogonal experiment are solid-liquid ratio of 1∶30(g/mL),pH of 3.0,ethanol volume fraction of 50%and ultrasonic time of 30 min,and then macroporous resins are used to separate and purify the anthocyanins obtained by crude extraction.The adsorption and desorption effects of six macroporous resins such as XDA-6,LX-16,LX-41,LX-180S,LK825,DM21 are compared.The results show that the adsorption rate and desorption rate of LK825 macroporous resin are 90.36%and 90.19%respectively,which has strong adsorption capacity and good desorption property.Therefore,LK825 macroporous resin is selected for purification test.The optimal conditions for the static test of LK825 macroporous resin are adsorption equilibrium time of 7 h,desorption equilibrium time of 5 h,extraction solution pH of 3.0,desorption solution pH of 3.0 and ethanol volume fraction in desorption solution of 60%.The optimal parameters of dynamic test are loading flow rate of 1.0 mL/min,loading solution volume of 22 BV,loading concentration of 1.0 mg/mL,elution flow rate of 1.5 mL/min and desorption solution volume of 9 BV.After purification,the content and color value of anthocyanins in blueberry residue are 12.8 times and 17.9 times of those before purification,and the purity is significantly improved.