IMPACT OF EXTRACTION SOLVENT ON THE PHENOLIC COMPOSITION AND ANTIOXIDANT PROPERTIES OF SEA FENNEL EXTRACTS : diploma thesis

Motar (Crithmum maritimum L.) je halofit koji je odavno poznat u mediteranskoj kuhinji, no zadnjih godina istraživanja sve više ukazuju na njegov ekonomski potencijal i širu primjenu u prehrambene i medicinske svrhe. Biljku odlikuje bogat izvor bioloških aktivnih komponenti uključujući vitamin C, minerale, fenolne spojeve, klorogensku kiselinu te snažna antioksidacijska moć. U ovom istraživanju proučavan je utjecaj različitih ekstrakcijskih otapala na izolaciju fenolnih spojeva iz motra te antioksidacijska aktivnost ekstrakata, korištenjem DPPH (engl. 2,2-diphenyl-1-picryl-hidrazyl-hidrate) i FRAP (engl. Ferric Reducing Antioxidant Power) metoda. Vodenim i etanolnim ekstraktima dobivenih primjenom ultrazvučne ekstrakcije (60 C, 60 Hz, 30 min) ispitan je i utjecaj na inhibicijsku sposobnost oksidacije sezamovog ulja Rancimat metodom (120 C, 20 L/h). Rezultati su pokazali da odabir ekstrakcijskog otapala ima utjecaj na ekstrakciju ukupnih fenola, ukupnih flavonoida, ukupnih tanina te na antioksidacijska svojstva ekstrakata motra. Ekstrakt dobiven korištenjem 50%-tnog etanola ima najviši udio ukupnih fenola i ukupnih flavonoida, dok ekstrakt pripravljen s 96%-tnim etanolom sadrži najviši udio ukupnih tanina. Na temelju dobivenih rezultata može se zaključiti da alkoholni ekstrakti motra pokazuju bolju antioksidacijsku aktivnost od vodenog ekstrakta, te da se s povećanjem udjela alkohola produljuje vrijeme indukcije ulja. S druge strane, vodeni ekstrakt ima negativan učinak na stabilnost ulja, odnosno pro oksidacijsko djelovanje.Sea fennel (Crithmum maritimum L.) is a halophyte that has long been known in Mediterranean cuisine, but its economic potential and uses in food and medicine have recently become an increasing focus of research. The plant is characterized by a rich source of bioactive components, including vitamin C, minerals, phenolic compounds, chlorogenic acid, and potent antioxidant properties. In this study, the influence of different extraction solvents on the isolation of phenolic compounds from sea fennel and the antioxidant capacity of the extracts obtained were investigated using the DPPH (2,2-diphenyl-1-picryl- hydrazyl-hydrate) and FRAP (Ferric Reducing Antioxidant Power) methods. The impact on the oxidative stability of sesame oil was also studied using water and ethanol extracts obtained by ultrasound-assisted extraction (60 °C, 60 Hz, 30 min) by the Rancimat method (120 °C, 20 L/h). The results showed that the choice of extraction solvent had an effect on the extraction of total phenols, total flavonoids, total tannins, and antioxidant properties of sea fennel. The extract with 50% ethanol had the highest content of total phenols and total flavonoids, while the extract with 96% ethanol had the highest content of total tannins. The results indicate that alcohol extracts of sea fennel have better antioxidant activity than water extract, and increasing the alcohol content in the extract prolongs the induction time of sesame oil. The water extracts, on the other hand, had negative effects on oil stability and prooxidant activity