Enrichment of Black Ripe Olives in Bioactive Compounds Using a Single Alkali Treatment.

Abstract

The aim of this work was to develop a method for processing ripe olives with a single NaOH treatment (lye) instead of the well-known 3 lye treatments. Olives of the Hojiblanca variety were processed according to the 2 processes and the color, firmness, flavor, and content in phenolic compounds of the final product were similar in both cases but concentration in triterpenic acids was highest in the olives from the single lye treatment. In this process the concentration of NaOH must range between 20 and 35 g/L, especially to obtain good texture when working at 20 °C. If temperature during the oxidation up to 27 °C the firmness of olives was significantly decreased. The concentration of the NaOH did not exert a high effect on the color of the final product, although firmness decreased as the strength of the lye increased. Higher contents in phenolic compounds and triterpenic acids were also found in the olives processed with the lowest NaOH concentration tested (20 g/L). This new process reduces the volume of wastewaters and energy consumption, and gives rise to a product which is richer in bioactive substances than the traditionally processed one.