Phenolic compounds change during California-style ripe olive processing

Changes in phenolic composition or. olive fruits (Olea europaea Intosso cv. ) during California-style ripe olive processing were investigated. Hydroxyt yrosol, tyrosol, oleuropein, oleuropein aglycones and oleoside-11- methyl e ster were the main phenols identified by GC and GC-MS techniques. During th e darkening process, only hydroxytyrosol decreased markedly and its diminut ion in flesh was directly related to the olive fruit browning development. Iron salts, used for colour fixation, seem to play a catalytic role in the oxidation of hydroxytyrosol and mechanisms involved in the browning are pro posed. (C) 2001 Elsevier Science Ltd. All rights reserved.