Olive Oil Extraction and Table Olive Industries

Production of olive oils (OOs) is a key industrial activity mainly in the countries of the Mediterranean Basin. As it is well known, the production of olives has two destinations: obtaining olive oils and generating table olives. Nowadays, production of olives is mainly directed to the extraction of olive oils, although world production of table olives was 2.5 106 tons in 2022, with an increase of 44% in the last 15 years. In recent years, and from the perspective of the production of early harvest virgin olive oils, it is worth highlighting the introduction of cold technology in preliminary external and internal operations and in the preparatory stages of olive pastes, fundamentally in the malaxation operation. In order to differentiate the oils produced between olive-growing regions, other milling equipment different to hammer mill has been introduced. The change in this type of mill, fundamentally, has two objectives: reduce the formation of emulsions and increase the effect of dilaceration. Recently, new technologies have been introduced to replace or reduce the malaxation stage: thermomechanical extruder (“Protoreattore”), ultra vacuum malaxation (“Booster”), paste treatment by electric pulses, and use of high-power ultrasounds. This equipment, tested at an industrial level in Spanish and Italian oil mills, seems to decrease the malaxation time and increase the organoleptic quality of virgin olive oils produced. Among the different historical milestones that have caused significant changes in the production of OOs, the incorporation of centrifugation technology allowed to replace extraction process by pressure, achieving a continuous separation and, with it, a leap towards the modernization of the sector. The replacement of the decanter with three outlets for those with two outlets resulted in the elimination of ‘alpechines’ (olive waste water), although a new olive pomace with high degrees of humidity is produced. From an environmental point of view, the change made can be considered positive, provided that there is an olive-pomace oil extraction industry that can manage these moist pomaces properly. Regarding the quality of the oils, the extraction systems using two-outlet decanter have led to products with a somewhat different composition, in general, a higher content of phenolic compounds, increasing the oxidative stability of the product. The future of the olive oil industry must move towards a greater interrelation between olive oil production, conservation of the environment and energy generation.