Utjecaj parametara ekstrakcije potpomognute mikrovalovima na sadržaj ukupnih fenola i antioksidacijsku aktivnost lista crnog ribiza

master's thesis

• Title (english): Effect of microwave-assisted extraction parameters on the content of total phenols and antioxidant activity of blackcurrant leaves
• Author: Tatjana Franković
• Mentor: Ivona Elez Garofulić (mentor)
• Mentor: Erika Dobroslavić (pomoć pri izradi, neposredni voditelj)
• Committee member: Verica Dragović-Uzelac (predsjednik povjerenstva)
• Committee member: Maja Repajić (član povjerenstva)
• Committee member: Sandra Balbino (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2023-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Cilj ovog rada bio je odrediti optimalne parametre ekstrakcije potpomognute mikrovalovima (MAE) za izolaciju fenolnih spojeva iz lista crnog ribiza te odrediti antioksidacijsku aktivnost (AOA) ekstrakta. Ekstrakt je dobiven pomoću MAE uz 30 %-tni etanol kao otapalo pri čemu je ispitan utjecaj temperature (60, 70 i 80 ℃), vremena ekstrakcije (5 i 10 min) te omjera otapala i uzorka (20, 30 i 40 mL g⁻¹). Maseni udio ukupnih fenolnih spojeva i AOA određeni su spektofotometrijski, a dobivene prosječne vrijednosti su iznosile: za fenolne spojeve 50,89 mg GAE g⁻¹, za AOA ABTS metodom 552,49 μmol TE g⁻¹, DPPH metodom 379,45 μmol TE g⁻¹ i FRAP metodom 503,20 μmol TE g⁻¹. Statistička analiza je pokazala kako temperatura i vrijeme trajanja ekstrakcije nisu značajno utjecali na sadržaj ukupnih fenola kao ni na AOA ekstrakata (p>0,05), dok se omjer otapala i uzorka pokazao kao statistički značajan parametar (p≤0,05) uzrokujući porast koncentracije ukupnih fenola i AOA prilikom primjene većih volumena otapala. Najveći udio fenolnih spojeva i najviša AOA zabilježeni su pri uvjetima MAE 60 °C/ 5 min/40 mL g⁻¹.

Abstract (english)

The aim of this study was to determine the optimal parameters of microwave-assisted extraction (MAE) for the isolation of phenolic compounds from blackcurrant leaves and to determine the antioxidant activity (AOA) of the extract. The extract was obtained using MAE with 30% ethanol as a solvent, where the influence of temperature (60, 70 and 80 ℃), extraction time (5 and 10 min) and the ratio of solvent and sample (20, 30 and 40 mL g⁻¹) was examined. The mass fraction of total phenolic compounds and AOA were determined spectrophotometrically, and the obtained average values were: for phenolic compounds 50.89 mg GAE g⁻¹, for AOA by the ABTS method 552.49 μmol TE g⁻¹, by the DPPH method 379.45 μmol TE g⁻¹ and by the FRAP method 503.20 μmol TE g⁻¹. Statistical analysis showed that the temperature and duration of the extraction did not significantly affect the content of total phenols, nor the AOA of the extracts (p>0.05), while the ratio of solvent to sample proved to be a statistically significant parameter (p≤0.05) causing an increase in the concentration of total phenols and AOA when using larger volumes of solvent. The highest content of phenolic compounds and the highest AOA were recorded under MAE conditions of 60 °C/ 5 min/40 mL g⁻¹ .

• Keywords: crni ribiz; list; MAE; fenolnih spojevi; antioksidacijska aktivnost
• Keywords (english): black currant; leaf; MAE; phenolic compounds; antioxidant activity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:998605
• Study programme: Title: 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 resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-06-07 11:26:36