Determination of Polyphenols and Vitamins in Wine-Making by-Products by Supercritical Fluid Extraction (SFE)

Fruits, vegetables, cereals and their derivatives are associated with the prevention or delay of chronic degenerative diseases, being a source of important constituents able to reduce oxidative cellular stress. Vitaceae (e.g., Vitis vinifera L.) are very rich in polyphenols, sterols and vitamins that are partially transferred to wine by-products during winemaking practices. As a result, the solid waste generated by the wine industry may represent a valuable source of these active biological compounds. In this paper, in order to ennoble grape waste, high-value extracts were obtained from pomace, skins and seeds employing a simple, green and inexpensive protocol involving carbon dioxide supercritical fluid extraction (SFE). The comparison with a conventional approach based on a solid-liquid extraction, in terms of the extract antioxidant capacity and total polyphenol content, as well as extraction yield of trans-resveratrol, beta-sitosterol, alpha-tocopherol and ascorbic acid, was carried out.