Extraction and Purification of Proanthocyanidin fromGrape Seed

摘要

The output of grapevine wastes(including grape seeds, skins and stems) in China is about100,000 ton per year, which contain many bioactive components such as resveratrol,phenolicacid,flavonol,proanthocyanidin (PC) etc. The main nutrients of Cabernet Sauvignon grape wastesinclude protein, fat, carbohydrates, dietary fiber and polyphenols. The contents of polyphenols(expressed as Garlic Acid Equivalents, GAE) in grape seeds, skins and stems are 1.82%,1.79% and4.85% respectively based on raw material with 10% of water,whereas the PC content was0.85%,0.72%, and 3.05% respectively. The research on storage of grape seeds shows that 30% ofPC lost in the first 2 months. However, the loss reduced in the following 3 months. The mostoptimum extraction of PC from grape seeds involved drying of the raw material in a vacuum ovenfollowed by crushing to 130-150 mesh, extraction with 70% acetone as solvents at 20°C for 40minutes with stirring. The extraction of PC reached to 99.11%. It was found that ultrasonic wavetreating is beneficial to protect PC from oxidation. The purification experiments of PC shows thatdifferent ethanol content of the elution solvents can affect the purity of PC products from HP -2MGLresin absorbed crude PC extracts,with ethanol content of 70%, the crude 60% PC is obtained. Thenthe crude PC is eluted through a Sephadex LH -20 column and eluted by 30%, 50%, and 70%methanol. Acetone (50%) was also used and the fraction obtained from the 50% acetone wasanalyzed with LC-MS. The results showed that the fraction was made up of polymers of catechin andepicatechin,while the content of oligomeric proanthocyanidin (OPC) is approximately 95% percent.