Useful Bioactive Substances from Wastes: Recovery of Trans-Resveratrol from Grapevine Stems

The methods for producing natural resveratrol are of big interest because of the many health benefits of this substance and its increasing use in functional foods, food supplements and para-pharmaceutical preparations. Generally, resveratrol is extracted from different natural sources, most of them usually produced for consumption purposes (grapes, nuts). This paper presents a method for recovery of resveratrol from a widely available raw material grapevine stems, a by-product of vine pruning. An efficient extraction-fractionation scheme is developed, based on shifting the phase equilibrium, by which more concentrated extracts of resveratrol are obtained. After a simple extraction, the initial extract is further separated into two fractions, containing either water or ethanol-soluble compounds. Using this approach, the resveratrol’s low water solubility helps isolate it from other water-soluble substances. The resulting product is almost ten times more concentrated in trans-resveratrol than the initial total extract. Additionally, a fraction containing water-soluble polyphenols is obtained, which could be used for water-based pharmaceutical and cosmetic preparations.