Separation, Isolation, and Enrichment of Samples of Phenolic Compounds from Winemaking By-Products

Abstract

Grapes, especially those of the red varieties, have a high content of polyphenolic compounds. After the removal of the juice during the winemaking process, the grape marc (peels and seeds) remains as waste, making it a promising source for the isolation of polyphenols. The separation, recovery, and enrichment of samples of phenolic compounds offers the possibility of their subsequent utilization in the food, pharmaceutical, and cosmetics industries. In this paper, results are presented on both laboratory and pilot scales, including the effect of basic extraction parameters such as the solvent (water, ethanol, acetone, polyethylene glycol, ethyl acetate, and their respective 50% aqueous solutions), the solid/liquid ratio, the extraction time, and the temperature. The enrichment of the extracts in phenolic compounds was performed with the help of a series of membrane processes and rotary evaporation. The experiments showed the presence of almost all known compounds reported in the literature with pro-anthocyanidins (dimers-trimers) and flavan-3-ols together with various metabolites accompanied by a significant reduction in the values of total organic load.