Understanding the Characteristics of Oleuropein for Table Olive Processing

Phenolic compounds make up 2-3% (w/w) of olive flesh, whose most abundant part is oleuropein which is responsible for the characteristic bitter taste of olive fruits. Oleuropein is a heterosidic ester of elenolic acid and hydroxytyrosol and possesses beneficial effects on human health. But most fundamental and important step of table olive processing is to reduce level of oleuropein because olive fruits can only be consumed after de-bittering procedures. Oleuropein accumulates during fruit growth and is slowly converted to elenolic acid glucoside and demethyloleuropein as the fruit ripens. Harvest maturation affects the table olive processing factors, according to change on oleuropein content of olive fruits. More severe applications are required for processing of olive which has high oleuropein content. Also oleuropein and its hydrolysis end products (elenolic acid and aglycone) inhibit the activity of a number of microorganisms involved in the lactic fermentation of olives. Oleuropein was significantly affected by both acid and base treatment, resulted in the liberation of hydroxytyrosol. Bitter taste of olive fruit can be eliminated by removing the oleuropein out of the olive or chemical or enzymatic hydrolysis of oleuropein in table olive processes. Understanding the characteristics of oleuropein for table olive processing helps manufacturer to produce high quality table olives and researchers to develop innovative methods for table olive production. So that this research was aimed to explore the characteristics of oleuropein and its effects on table olive processes.