Extraction and Purification of Resveratrol from Grape Waste

The current study aimed to extract and purify the phenolic compound Resveratrol from dried blackgrape residues, Vitis vinifera, which were purchased from the local market in Iraq. Resveratrol wasextracted from sun-dried grape residues with 2.5 liters of 80% ethanol. Then the compound resveratrolwas concentrated using a rotary evaporator and dried in very high freezing conditions after beingfiltered with animal charcoal. A partially purified material was obtained after a column chromatographyprocess, where 9 grams were obtained for every 600 grams of grape residues as a result of these steps.Chemical tests were conducted to detect resveratrol, and they included: general tests for polyphenols,detection of unsaturated cyclic compounds, high-efficiency liquid chromatography (HPLC) method.The results showed the appearance of two peaks at a wavelength of 280 nm for the compound resveratrolextracted from grape residues, where the time of its appearance was at 4.267 /min compared with thestandard compound resveratrol which was at 4.356 /min. The concentration of the resveratrol extractwas 107.6 ppm. The total antioxidant activity of resveratrol extracted from grape residues and thestandard compound resveratrol was estimated. The total antioxidant activity of resveratrol extractedfrom grape residues was 71.14%, while it was 62.21% for the standard compound resveratrol. Theresults showed that the resveratrol compound extracted from grape residues was purified in the darkto prevent the conversion of resveratrol from trans to cis. The study also shed light on the quantities ofresveratrol contained in grape residues, and this depends on the extraction steps as well as the purposeof its applications.