Extraction and Purification of Resveratrol from Grape Waste

Abstract

The current study aimed to extract and purify the phenolic compound Resveratrol from dried black
grape residues, Vitis vinifera, which were purchased from the local market in Iraq. Resveratrol was
extracted from sun-dried grape residues with 2.5 liters of 80% ethanol. Then the compound resveratrol
was concentrated using a rotary evaporator and dried in very high freezing conditions after being
filtered with animal charcoal. A partially purified material was obtained after a column chromatography
process, 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 resveratrol
extracted from grape residues, where the time of its appearance was at 4.267 /min compared with the
standard compound resveratrol which was at 4.356 /min. The concentration of the resveratrol extract
was 107.6 ppm. The total antioxidant activity of resveratrol extracted from grape residues and the
standard compound resveratrol was estimated. The total antioxidant activity of resveratrol extracted
from grape residues was 71.14%, while it was 62.21% for the standard compound resveratrol. The
results showed that the resveratrol compound extracted from grape residues was purified in the dark
to prevent the conversion of resveratrol from trans to cis. The study also shed light on the quantities of
resveratrol contained in grape residues, and this depends on the extraction steps as well as the purpose
of its applications.