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master's thesis
Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja
Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. urn:nbn:hr:159:206544
Poljanec, Andreja
University of Zagreb
Faculty of Food Technology and Biotechnology
Department of Food Engineering
Laboratory for Food Processes Engineering

Institutional repository: Repository of the Faculty of Food Technology and Biotechnology

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Poljanec, A. (2019). Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja (Master's thesis). Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:159:206544

Poljanec, Andreja. "Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja." Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. https://urn.nsk.hr/urn:nbn:hr:159:206544

Poljanec, Andreja. "Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja." Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, 2019. https://urn.nsk.hr/urn:nbn:hr:159:206544

Poljanec, A. (2019). 'Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja', Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, accessed 07 October 2024, https://urn.nsk.hr/urn:nbn:hr:159:206544

Poljanec A. Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja [Master's thesis]. Zagreb: University of Zagreb, Faculty of Food Technology and Biotechnology; 2019 [cited 2024 October 07] Available at: https://urn.nsk.hr/urn:nbn:hr:159:206544

A. Poljanec, "Određivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja", Master's thesis, University of Zagreb, Faculty of Food Technology and Biotechnology, Zagreb, 2019. Available at: https://urn.nsk.hr/urn:nbn:hr:159:206544

Metadata
TitleOdređivanje fenolnih spojeva i antioksidativne aktivnosti dobivenih ekstrakata lista masline nakon visokonaponskog pražnjenja
Title (english)Determination of polyphenolic compounds and antioxidant activity of extracts from olive leaves by means of high voltage electrical discharges
AuthorAndreja Poljanec
MentorAnet Režek Jambrak (mentor)
GranterUniversity of Zagreb
Faculty of Food Technology and Biotechnology
(Department of Food Engineering)
(Laboratory for Food Processes Engineering)
Zagreb
Defense date and country2019-09-20, Croatia
Scientific / art field,
discipline and subdiscipline		BIOTECHNICAL SCIENCES
Food Technology
Abstract
Listovi masline smatraju se jeftinom sirovinom koja može poslužiti kao izvor visokovrijednih bioaktivnih spojeva, s potencijalnom primjenom u prehrambenoj industriji. Svrha ovog istraživanja bila je utvrditi učinak visokonaponskog električnog pražnjenja (HVED), kao zelene metode ekstrakcije, na efikasnost ekstrakcije fenolnih spojeva iz lista masline te usporediti HVED metodu s konvencionalnom metodom ekstrakcije. HVED tretman provodio se kroz različito vrijeme (3 i 9 min), u različitim zelenim otapalima (voda, etanol), radnim plinovima (dušik, argon) i pri različitim naponima (15, 20, 25 kV). Fenolni spojevi određeni su pomoću tekućinske kromatografije ultra visoke djelotvornosti s detekcijom masene spektrometrije (UPLC-MS/MS), dok su udio ukupnih fenola i antioksidacijska aktivnost određeni spektrofotometrijski. Prikazani su i rezultati blisko-infracrvene (NIR) spektroskopije i veličine čestica ekstrakta lista masline. Najveći prinos fenolnih spojeva uočen je u uzorku tretiranom argonom, 9 min, 20 kV i u 50 %-tnoj otopini etanola. Antioksidacijska aktivnost određena FRAP metodom bila je veća u HVED tretiranim uzorcima, dok DPPH i ORAC metoda nisu pokazale značajnu razliku nakon HVED tretmana. Razvijeni su i regresijski modeli za predviđanje sadržaja ukupnih fenola i antioksidacijske aktivnosti sličnih uzoraka na temelju analitičkih podataka i NIR spektroskopije.
Abstract (english)
Olive leaves are considered as a cheap raw material which can be used as a source of valuable bioactive compounds, with potential application in food industry. The aim of this study was to evaluate high voltage electrical discharges (HVED) as a green technology, in order to establish the effectiveness phenolic extraction from olive leaves and compare HVED method with conventional extraction. HVED processing parameters were: treatment time (3 and 9 min), different green solvents (water, ethanol), working gases (nitrogen, argon) and voltages (15, 20, 25 kV). Individual phenolic compounds were characterized by ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS), while the content of total phenolics and antioxidant activity were determined spectrofotometrically. Results for Near infrared (NIR) spectroscopy and particle size of olive leaves extract were also reported. The highest yield of phenolic compounds was obtained for the sample treated with argon, 9 min, 20 kV and 50 % solution of ethanol. Antioxidant activity determined by FRAP method was higher in HVED treated samples, while DPPH and ORAC method showed no significant difference upon the HVED treatment. Regression models were developed for prediction total phenolic content and antioxidant activity of similar samples based on analytical data and NIR spectroscopy.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:159:206544
Study programmeTitle: Food Engineering
Study programme type: university
Study level: graduate
Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
Type of resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0) icon
Created on2020-01-28 14:03:34