Extraction And Purification Of Total Flavonoids From Blueberry Residue And Study On Their Antioxidant Properties

Blueberry residue is the waste product of blueberry brewing or juicing.The extraction of total flavonoids from blueberry residue can not only enrich the variety of blueberry processing products,but also improve the economic value of blueberry processing by-products.At present,the research on blueberry flavonoids mainly focuses on the blueberry fruit,while the research on the extraction of total flavonoids from the waste blueberry residue is limited.In this paper,the extraction and purification process of total flavonoids from blueberry residue was studied,and the antioxidant properties of flavonoids were tested.The main research contents and results of this paper are as follows:The optimum level of each factor was determined by single factor experiment with the yield of total flavonoids as the evaluation index.On the basis of single factor experiment,was studied by the response surface test of ethanol concentration,solid-liquid ratio,ultrasonic time,ultrasonic power on the extraction yield,the influence of analysis to get optimum technological parameters for extraction: ethanol concentration of 60%,material-liquid ratio of 1:25g/m L,ultrasonic time of 45 min,and ultrasonic power of 290 W,under this condition,blueberries slag extraction yield of total flavonoids was 4.900±0.012%.By comparing the adsorption and desorption properties of 5 macroporous resins to total flavonoids from blueberry residue,the optimum resin SP70 was obtained.Through the static and dynamic tests of SP70 resin,the optimal process parameters for the purification of total flavonoids from blueberry residue were obtained: sample concentration 1.47mg/m L,sample p H=3.5,ethanol concentration 70%,sample volume 30 m L(10.0g resin),sample flow rate 1.5m L/min,elution volume 100 m L,elution flow rate 1.0m L/min.Under the optimum purification process,the purity of total flavonoids in blueberry residue increased from 10.52%to 64.56%,and the purification effect was better.The scavenging capacity of total flavonoids for DPPH· free radical and ·OH free radical was investigated with VC as the control,and the antioxidant activity of total flavonoids from blueberry residue was studied.The IC50 values of DPPH· and ·OH radical scavenging rate of total flavonoids were 0.0200mg/m L and 0.3286mg/m L.The scavenging capacity of total flavonoids for ·OH free radical was better than that of VC,while the scavenging capacity of DPPH· free radical was weaker than that of VC,indicating that total flavonoids of blueberry residue had better antioxidant activity.