Impact of storage conditions on the aromatic profile of virgin olive oils : bachelor thesis

Abstract

Maslina (Olea europea) jedna je od najstarijih kultiviranih biljaka i ključna kultura u jadranskom dijelu Hrvatske. Djevičanska maslinova ulja, proizvedena isključivo mehaničkim postupcima tiještenja zdravih plodova masline, izdvajaju se svojim jedinstvenim sastavom i aromom. Hlapljivi spojevi koji se razvijaju tijekom i nakon ekstrakcije ulja značajno doprinose njegovom aromatičnom profilu. Osim berbe i prerade, na kvalitetu maslinovog ulja utječu adekvatna dorada i pravilno skladištenje, što je ključno za očuvanje ulja i zaštitu od štetnih vanjskih utjecaja. Cilj ovog Završnog rada bio je ispitati utjecaj načina čuvanja djevičanskog maslinovog ulja, dobivenog preradom različitih sorti maslina (Oblica, Leccino i Levantinka) ubranih s dva različita lokaliteta, na aromatični profil ulja. Uzroci su čuvani na tri načina: u tamnoj staklenoj boci na suhom i tamnom mjestu, u inox spremniku te u inox spremniku s dušikom u natprostoru. Analize su provedene svako 6 mjeseci u periodu od 18 mjeseci. Iz dobivenih rezultata utvrđeno je da odabir načina čuvanja ima izražen utjecaj na aromatični profil djevičanskih maslinovih ulja. Rezultati svih načina čuvanja ulja pokazali su blagi trend pada hlapljivih spojeva koji se povezuju pozitivnim aromama. Čuvanje ulja u tamnoj staklenoj boci i inox spremnicima s dušikom u natprostoru se pokazalo kao izrazito dobar način čuvanja, naročito za sprječavanja procesa oksidacije. Ulja čuvana u inox spremniku bez korištenja dušika u natprostoru bila su podložnija procesima oksidacije što je rezultiralo povećanim udjelom hlapljivih spojeva koji se povezuju s negativnim aromama ulja.The olive (lat. Olea europea) is one of the oldest cultivated plants and a key crop in the Adriatic region of Croatia. Virgin olive oils, produced exclusively through mechanical processes by pressing healthy olive fruits, stand out due to their unique composition and aroma. The volatile compounds that develop during and after the oil extraction significantly contribute to its aromatic profile. In addition to harvesting and processing, the quality of olive oil is influenced by appropriate refinement and proper storage, which are crucial for preserving the oil and protecting it from harmful external factors. The aim of this thesis was to investigate the impact of storage methods on the aromatic profile of virgin olive oil obtained from the processing of different olive varieties (Oblica, Leccino, and Levantinka) harvested from two different locations. The samples were stored in three different ways: in a dark glass bottle in a dry and dark place, in a stainless steel tank, and in a stainless steel tank with nitrogen in the headspace. Analyses were conducted every six months over a period of 18 months. The results indicated that the choice of storage condition has a significant effect on the aromatic profile of the virgin olive oil. The results of all methods of oil storage showed a slight trend of decreasing volatile compounds associated with positive aromas. Storing the oil in a dark glass bottle and in nitrogen-filled stainless steel tanks proved to be an extremely effective way to preserve the oil, particularly in preventing oxidation processes. In contrast, oils stored in a stainless steel tank without using nitrogen in the headspace were more susceptible to oxidation processes, which resulted in an increased proportion of volatile compounds that are associated with the negative aromas of the oil