Recovery of phenolic compounds from Olea europaea

The recovery of biophenols from olive drupes by simple extraction (free phenolics) was compared to that from acid- and base-treated extracts. Quantitative data are presented for levels of phenols obtained by the different procedures. The major phenol in green olives, oleuropein, was significantly affected by both acid- and base-treatment, and resulted in the liberation of hydroxytyrosol glucoside. The level of hydroxytyrosol glucoside produced after 24h of acid-treatment was approximately 50 times that produced in base-treated extracts.