Simple phenolic content in olive oil residues as a function of extraction systems

Olive oil residues were tested for their composition in simple phenolic com pounds as a function of the extraction system, i.e. the three- and two-phas e centrifugation systems. Phenolic compound extraction with ethyl acetate w as efficient and allowed recovery of 28.8 and 42.2% of total phenols presen t in dry olive oil residues originating from three-phase and two-phase syst ems, respectively. The qualitative and quantitative HPLC analyses of the ex tracts showed that hydroxytyrosol and p-tyrosol were the most abundant phen olic compounds. p-coumaric, caffeic, ferulic and vanillic acids were also p resent. The phenolic extract from the two-phase system had the highest conc entration in hydroxytyrosol (1.16% (w/w) dry residue) and the strongest ant ioxidant activity. Olive oil residues were confirmed as a cheap source of l arge amounts of natural phenolic antioxidants. (C) 2001 Elsevier Science Lt d. All rights reserved.