Effect of Washing with Acidified Water during Processing on the Quality of Spanish-Style Green Table Olive

Table olives are one of the most consumed appetizers in the world. Egypt is currently the largest producer of table olives in the world. Manzanilla is the most valued table olive variety of preparation for Spanish-style green olive, in this technique, the olive fruits are sorted, graded by size and finally treated with a dilute 1.5% (w/v) sodium hydroxide solution to remove bitterness (glucoside oleuropein). After this treatment, olives are washed with tap water several times at least 3 times to eliminate the excess of alkali. Washing waters of Spanish-style green olive processing are heavily contaminated waste streams that represent an important environmental problem that needs to be solved. The aim of this study was to evaluate the use of acidified water (HCl 1% or H₂SO₄ 1%) in washing of olive fruits treated with alkaline as well as the efficacy of this technique on the resultant fruits quality and sustainability of water used. The obtained results demonstrated that the possibility of olive fruits were washed after lye- treatment to only one time, by using acidified water with HCl 1% (WAW_HCl) or with 1% H₂SO₄ (WAW_H2SO4) compared with fresh water (3 times), and the re-use of resultant wastewater after neutralization with HCl 7% as a safe water for irrigation. Oleuropein is responsible for bitterness, its content decreased during processing and fermentation in all treatments. Regarding sensory properties of olive pickles (WAW_H2SO4) gave the lowest score of defects 0.5% meanwhile high score of smell (8) and taste (9). The study concluded obviously that the possibility to use acidified water (H₂SO₄ 1%) in olive fruits washing after lye-treatment without any changes in the olive pickles quality.