The effects of ultrasound and ozone applications in the processing of Gemlik black table olives

Turkey is ranked third in the world in black olive production, a large majority of this production constitutes Gemlik black olives. Although the traditional methods that are used to eliminate bitterness by using various chemicals in olive processing are applied widely, they have been searched for additional alternative methods due to their negative health effects and long fermentation process. In this study, ultrasound and ozone tech-nologies were used to eliminate olive bitterness. The effects of these applications on the microbiological, physical and chemical properties of Gemlik black olives were investiga-ted. The harvested black olives were taken into brine with two different brine concentra-tions after various pretreatments; ultrasound and ultrasound-ozone were applied toget-her for one week, then lactic acid bacteria were inoculated and left for a two-month fermentation process. Microbiological, physical and chemical analyzes were carried out periodically in olive samples after treatment and fermentation, and the process was fol-lowed up by performing the development test periodically after treatment. It was obser-ved that the application of ozone prevented the formation of total mezophilic aerob bac-teria, mold, yeast and enterobacter, decreased the pH below 4,5 in all samples. After the treatment and fermentation, the amount of dry matter and pH decreased, the amount of ash and total acidity increased. While there was no significant change in salt values after the treatment, it increased as a result of fermentation. As a result of ozone application, a decrease in color values (a*and b*) was observed and did not cause a significant change in L value. There was no negative effect of ultrasound and ozone applications on fruit tissue. It has been seen that the application of ultrasound accelerates the Na transition to the fruit and its use with ozone makes an important contribution to Ca transition. In ad-dition, it was concluded that the total amount of phenolic substance varies depending on the treatments and brine concentrations.