Thesis Dissertation (Abdelaziz Boudebouz): Effect of Agronomic and Technological Factors on the formation of Ethyl Esters in Virgin Olive Oil in Catalonia
Abdelaziz Boudebouz
29/07/2021
Departament de Química Analítica i Química Orgànica
Institut de Recerca i Tecnologia Agroalimentaria (IRTA)
Directores: Dr. Ricard Boqué Martí, Dra. Montserrat Mestres Solé i Dr. Agustí Romero Aroca.
Defensa online: Microsoft Teams
Scope
THE VIRGIN OLIVE OIL sector is one of the most important economically and culturally in the entire Mediterranean basin, including Catalonia. The peculiarities of Catalonia, located in the northeast of the Iberian Peninsula, are the small size of the orchards and the variable size of the milling facilities, which implies strengths and weaknesses for the quality of oil. Although Catalonia represents only 6% of total Spanish production, its producers are very aware of the quality of olive oil, as 85% of the oils produced are of extra virgin category. Therefore, the Catalan olive oil sector is aware of the entry into force of any new quality index in the Official Regulations.
The quality parameter more recently included in the Official Standard is the content of ethyl esters of fatty acids. This parameter distinguishes extra virgin olive oil from other oil qualities by limiting the maximum amount to 35 mg/kg.
THE FATTY ACID ETHYL ESTERS are used as a marker for the freshness, quality and good handling of olives throughout the processing of olive oil. However, because these compounds result from a rapid esterification reaction between free fatty acids and ethanol, it is also necessary to prevent the formation of these precursors to avoid large amounts of ethyl esters. Thus, the factors that influence the formation of precursors must be controlled, both agronomic factors (variety and ripening stage) and technological ones (postharvest management, extraction process and storage conditions).
CATALONIA has different autochthonous olive varieties for the production of olive oil, with the 'Arbequina' variety being the most widespread. In addition, there are significant variations in the production conditions between the different olive growing areas, in particular those in southern Catalonia.
Currently, several studies reflect and describe the factors that increase the free acidity of olive oil; however, there is still little information on short chain alcohol synthesis, which through esterification with the free fatty acids deliver alkyl esters.
Taking into account the above, this thesis aims to study the key factors that can increase the content of alcohols (both in olives and in olive oil) because this increases the risk of formation of alkyl esters. It should be noted that in this thesis all postharvest and processing experiments were carried out in real conditions to obtain the most representative results possible.
