Supercritical fluid extraction of pharmaceutic compounds from waste materials derived from vinification processes

Grape cultivation dates back to approximately 6000-8000 years ago. Nowadays it is still one of the major crops produced worldwide, mostly for wine production. Accordingly, grape pomace, the solid remain of the wine making process, is produced in large quantities. The disposal of such waste material is an issue of great ecologic and economic importance. Some wineries use the material as a fertilizer, while others are selling it to biogas companies for energy production. However, grape pomace possesses a much higher potential. Pomace is composed of grape seeds, stems, pulps and skins and contains pharmaceutically interesting polyphenolic compounds such as catechin, epicatechin, trans-resveratrol and procyanidin B1. Such compounds have beneficial effects on human health including antioxidant, anti-inflammatory, antidiabetic and anticarcinogenic activities. Such interesting compounds may be extracted from grape pomace by the use of organic solvents, however this procedure has several limitations, including solvent toxicity and the non-selectivity of the extraction towards lipophilic compounds. Alternative extraction technologies focus on the use of supercritical fluids. Supercritical CO2 is the most commonly used solvent, since it is non-toxic, inert and has modest critical values in terms of temperature and pressure, making its use industrially appealing. By the use of supercritical fluids extraction, high-quality extracts can be obtained from a variety of raw materials, including grapes, grape seeds and grape pomace.