HPLC-DAD i NMR analiza polifenola u maslinovom ulju

master's thesis

• Title (english): HPLC-DAD i NMR analysis of polyphenols in olive oil
• Author: Leona Burčak
• Mentor: Cvijeta Jakobušić Brala (mentor)
• Mentor: Monika Barbarić (mentor)
• Committee member: Cvijeta Jakobušić Brala (predsjednik povjerenstva)
• Committee member: Monika Barbarić (član povjerenstva)
• Committee member: Ana Karković Marković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of physical chemistry); Zagreb
• Defense date and country: 2021-12-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Medical Biochemistry

Abstract

Maslinovo ulje namirnica je koja ima impresivan kemijski sastav, a posebno je zanimljiv njezin sadržaj polifenola, čije se antioksidativno djelovanje na organizam razvija, čak i pri niskim koncentracijama. Jedan je od važnijih ciljeva prilikom analize polifenola u maslinovu ulju dobiti što točniji odnos između izmjerene (stvarne) koncentracije komponente u uzorku s koncentracijom koja u konačnici dospije do ciljnih mjesta u organizmu i djeluje na biološke procese. HPLC i NMR dvije su standardizirane metode za određivanje sadržaja određenih fenolnih spojeva u ekstraktima maslinovih ulja. Sadržaj oleokantala i oleaceina određivao se u ekstraktima koji su pripremljeni primjenom acetonitrila i cikloheksana i primjenom NMR spektroskopije, dok se sadržaj hidroksitirozola, tirozola, pinorezinola, cimetne kiseline i apigenina odredio u eksztraktima koji su pripremljeni primjenom metanola i heksana primjenom HPLC-DAD spektroskopije. Ispitan je polifenolan sastav šest maslinovih ulja autohtonih hrvatskih sorti masline: Rosulja (Oleum Viride), Buža (Brist), Bjelica (Brist i Oleum Viride), Vodnjanska crnica (Oleum Viride) i Višesortno ulje Istra. Sadržaj pojedinih fenolnih spojeva razlikovao se ovisno o sorti masline. U većini ispitanih sorti sadržaj oleaceina bio je viši od sadržaja oleokantala, što je u skladu s dosad dostupnim podacima o hrvatskim sortama, dok je suprotan odnos tih dvaju fenola utvrđen u većini maslinovih ulja drugih geografskih područja. Ispitana maslinova ulja mogu se smatrati dobrim izvorom polifenolnih sastavnica i ona upućuju na iznimnu kvalitetu ovih ulja s područja Republike Hrvatske. Nakon provedenih analiza uspoređene su obje metode ekstrakcije kako bi se utvrdio optimalni postupak pripreme ekstrakta za daljnja biološka istraživanja. Postupak je proveden tako da su oba ekstrakta puštena i na HPLC i na NMR (bez obzira na to za koju je metodu ekstrakcija razvijena). Usporedbe ekstrakcijskih metoda ipak nisu dale zadovoljavajuće rezultate.

Abstract (english)

Olive oil is a food that has an impressive chemical composition and it is especially interesting in the context of polyphenols, whose antioxidant activity in the body develops even at low concentrations. One of the most important goals in the analysis of polyphenols in olive oil is to obtain the most accurate relationship between the measured (actual) concentration of the component in the sample with the concentration that ultimately reaches targeted sites in the cells and affects biological processes in them. HPLC and NMR are two standardized methods for determining the concentration of certain phenolic compounds in olive oil extracts. The concentration of oleocanthal and oleacein was determined in extracts prepared using acetonitrile and cyclohexane and analysed by NMR spectroscopy, while the concentration of hydroxytyrosol, tyrosol, pinoresinol, cinnamic acid and apigenin was determined in extracts prepared using methanol and hexane using HPLC-DAD spectroscopy.The polyphenolic composition of six olive oils of autochthonous Croatian olive varieties was tested: Rosulja (Oleum Viride), Buža (Brist), Bjelica (Brist and Oleum Viride), Vodnjanska crnica (Oleum Viride) and Multi-varietal oil Istra. The content of individual phenolic compounds differed depending on the olive variety. In most of the examined cultivars, the oleacein concentration was higher than the oleocanthal, which is in line with the previous data available so far on Croatian cultivars, while the opposite ratio of these two phenols was found in olive oils cultivated in other geographical regions. The tested olive oils can be considered a good source of polyphenolic components and indicator of the exceptional quality of these oils from the territory of the Republic of Croatia. After analysis, both methods of extractions were compared in order to determine the optimal procedure for preparing the extracts for further biological research. The procedure was performed so that both extracts were run on both HPLC and NMR (regardless of which extraction method was used). However, comparisons of these two methods for extraction did not give satisfactory results.

• Keywords: polifenoli; maslinovo ulje; NMR; HPLC; oleacein; oleokantal
• Keywords (english): polyphenols; olive oil; NMR; HPLC; oleacein; oleocanthal
• Language: croatian
• URN:NBN: urn:nbn:hr:163:086895
• Study programme: Title: Medical biochemistry; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra medicinske biokemije i laboratorijske medicine (magistar/magistra medicinske biokemije i laboratorijske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-11-03 13:06:19