Antioksidacijska aktivnost i određivanje ukupnih fenola mikrovalnih ekstrakata biljke Borago officinalis L.

undergraduate thesis

• Title (english): Antioxidant activity and determination of total phenols in microwave extracts of the plant Borago officinalis L.
• Author: Anja Rašić
• Mentor: Filip Šupljika (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Physical Chemistry and Corrosion); Zagreb
• Defense date and country: 2024-06-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovoga rada bio je ispitati antioksidacijsku aktivnost i koncentracije ukupnih fenola ekstrakata biljke Borago officinalis L., dobivenih mikrovalnom ekstrakcijom. Ekstrakcije su provedene s deionoziranom vodom te 30 % tnom, 70 % -tnom vodenom otopinom etanola i 96 % -tnim etanolom pri temperaturama od 40, 60 i 80 ℃. Antioksidacijska svojstva ekstrakata ispitivana su DPPH i FRAP metodom, primjenom UV/VIS spektroskopije. Koncentracije ukupnih fenola također su određivane primjenom UV/VIS spektroskopije pomoću Folin – Ciocalteu reagensa. Najvišu koncentraciju ukupnih fenola pokazuje uzorak kod kojeg je kao otapalo korištena 70 % -tna vodena otopina etanola, a mikrovalna ekstrakcija je provedena pri 80 ℃. Taj uzorak ujedno pokazuje i najvišu antioksidacijsku aktivnost mjerenu DPPH metodom. Najvišu antioksidacijsku aktivnost određivanu FRAP metodom pokazuje ekstrakt gdje je kao otapalo korištena 30 % -tna vodena otopina etanola te je mikrovalna ekstrakcija provedena pri 80 ℃. 96 % -tni etanolni ekstrakti imaju najnižu antioksidacijsku aktivnost i najmanji sadržaj fenola određen svim trima metodama. Na antioksidacijsku aktivnost ekstrakata Borago officinalis L. utječu temperatura ekstrakcije i otapalo korišteno za ekstrakciju.

Abstract (english)

The aim of this thesis was to investigate the antioxidant activity and total phenol concentrations of Borago officinalis L. plant extracts obtained by microwave extraction. Extractions were performed with deionized water and 30 %, 70 %, 96 % ethanol at temperatures of 40, 60, and 80 ℃. The antioxidant properties of the extracts were examined using the DPPH and FRAP methods, employing UV/VIS spectroscopy. Total phenol concentrations were also determined using UV/VIS spectroscopy and the FolinCiocalteu reagent. The highest concentration of total phenols was found in the sample where 70 % ethanol was used as the solvent, and microwave extraction was conducted at 80 ℃. This sample also exhibited the highest antioxidant activity measured by the DPPH method. The highest antioxidant activity determined by the FRAP method was shown by the extract where 30 % ethanol was used as the solvent, and microwave extraction was conducted at 80 ℃. The 96% ethanol extracts showed the lowest values determined by all three methods. The antioxidant activity of Borago officinalis L. extracts is influenced by the extraction temperature and the solvent used for extraction.

• Keywords: antioksidacijska aktivnost; polifenoli; DPPH metoda; FRAP metoda; Borago officinalis L.
• Keywords (english): antioxidant activity; polyphenols; DPPH assay; FRAP assay; Borago officinalis L.
• Language: croatian
• URN:NBN: urn:nbn:hr:159:529382
• Study programme: Title: Food Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-11-08 09:52:30