Understanding the Characteristics of Oleuropein for Table Olive Processing

Aysun Ozturk

doi:10.4172/2157-7110.1000328

Abstract

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.

Highlights

Oleuropein, a bitter-tasting secoiridoids glycoside present in olive leaves and fruits, is the main phenolic compound in olive fruits it undergoes a notable decrease during the course of fruit ripening and 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 [8]
The disadvantages of debittering by NaOH are degradation of other phenolic compounds with oleuropein, nutrient losses caused by washing for removing the excess NaOH from olive and the formation of high amounts of waste water

Summary

Introduction

Oleuropein, a bitter-tasting secoiridoids glycoside present in olive leaves and fruits, is the main phenolic compound in olive fruits it undergoes a notable decrease during the course of fruit ripening and processing. For this reason the nutritional intake of oleuropein is usually considered as questionable [1,2]. The main purpose of table olives processing is the removal of bitterness related to oleuropein [5]. Bitter taste of olive fruit can be eliminated by enzymatic hydrolysis of oleuropein or semi drying processing of olives in table olive processes [6,7]. This review was aimed to explore the characteristics of oleuropein, remove or degradation of oleuropein and transformation of oleuropein during olive processing

Objectives

Findings

Conclusion