Recovery of phenolic compounds from Olea europaea

The recovery of biophenols from olive drupes by simple extraction (free phe nolics) was compared to that from acid- and base-treated extracts. Quantita tive data are presented for levels of phenols obtained by the different pro cedures. The major phenol in green olives, oleuropein, was significantly af fected by both acid- and base-treatment, and resulted in the liberation of hydroxytyrosol glucoside. The level of hydroxytyrosol glucoside produced af ter 24 h of acid-treatment was approximately 50 times that produced in base -treated extracts. (C) 2001 Elsevier Science B.V. All rights reserved.