Olives are a typical crop of the Mediterranean region. According to Eurostat data (Eurostat, 2019), olive tree farms are found in eight EU Member States: Spain (2.5 million hectares), Italy (1.1 million hectares), Greece (671 thousand hectares), Portugal (300 thousand hectares), Croatia (17 thousand hectares), France (15 thousand hectares), Cyprus (10 thousand hectares) and Slovakia (1 thousand hectares). In total, the European olive tree farms are slightly under 5 million hectares, more than half of which are in Spain and most of which are devoted to growing olives for olive oil production (Rossi, 2017). The International Olive Council (IOC) reported that world olive oil production is 2.9 million tonnes (t) in the 2017-2018 crop year. The joint production of four European countries (Spain, Italy, Greece and Portugal) takes the lead, which is approximately 1.8 million t (IOC, 2018a). The European Union is the main economy of the consumption of olive oil, which accounts for 53% of the world market, followed by the United States, which accounts for 10% (IOC, 2018b). Furthermore, a rapid increase in the demand for olive oil has been noticed in India, China and Japan.Olive oil is extracted from olive fruit via a mechanical or chemical process (Ou et al., 2015). It consists mainly of oleic acid and small amounts of other fatty acids (FAs). Furthermore, olive oil is an important constituent of the diet in the Mediterranean countries. It has also been reported to prevent some pathologies, e.g. cardiovascular disease, neurodegeneration, obesity, metabolic syndrome, diabetes and diverse types of cancer (