Characterization and recovery of phenolic compounds from grape pomace -A review

Recent findings have indicated potential health-beneficial effects of plant secondary metabolites, such as polyphenolics and carotenoids. Due to their widespread occurrence in plant foods, a diet rich in fruits and vegetables has been propagated by health authorities, as can be seen from the '5 a day campaign'. On the other hand sources are being searched for the recovery of phenolic compounds which may be used for the production of functional or enriched foods. Therefore, in a comprehensive screening the contents of individual phenolic compounds were determined in the skins and seeds of 14 grape pomace samples originating from red and white winemaking. The results indicate by-products of winemaking to be an inexpensive source for a wide range of different polyphenolics. With those pomace samples exhibiting the highest polyphenol levels a novel process for their extraction was developed on a pilot-plant scale, employing cell wall degrading enzymes for an enhanced release of phenolics. Finally, the crude extracts were purified using the adsorber technology to obtain a highly concentrated purified polyphenol extract.