Preparation method of oligomeric proanthocyanidin

[0021] 100 kilograms of cranberry fruits are mixed with 500 kilograms of 30% ethanol water solution, and extracted with a high-voltage pulsed electric field extractor. The extraction temperature is 25°C, the extraction time is 20min, the electric field intensity is 11kv / cm, and the pulse number is 15. Collect Extract solution: Concentrate the extract solution under reduced pressure, the concentrated vacuum degree is -0.08~-0.07MPa, the concentration temperature is 60±2°C, and the concentrated solution is concentrated until the volume fraction of ethanol is 1%; the concentrated solution is first centrifuged with a horizontal spiral sedimentation The centrifuge was centrifuged at a speed of 2000r / min, and the centrifugate was collected. The centrifugate is treated with a microfiltration membrane and an ultrafiltration membrane in turn. Both the microfiltration membrane and the ultrafiltration membrane are made of vinylidene fluoride (PVDF). 35°C, the pore size of the ultrafiltr

[0023] Mix 100 kilograms of grape seeds with 800 kilograms of 50% ethanol aqueous solution, extract with a high-voltage pulsed electric field extractor, the extraction temperature is 35°C, the extraction time is 30min, the electric field strength is 15kv / cm, and the number of pulses is 20, and the extract is collected Concentrate the extract under reduced pressure, the concentrated vacuum is -0.08~-0.07MPa, the concentration temperature is 60±2°C, and the concentrated solution is concentrated to a volume fraction of ethanol of 2%; the concentrated solution is first centrifuged with a tubular centrifuge, The rotating speed is 4000r / min, and the centrifugate is collected. The centrifugate is treated with microfiltration membrane and ultrafiltration membrane in turn. The materials of microfiltration membrane and ultrafiltration membrane are all selected from vinylidene fluoride (PVDF). 30°C, the pore size of the ultrafiltration membrane is 1000Dal, the temperature of the feed li