Antioksidativna aktivnost svježih i prženih lješnjaka

undergraduate thesis

• Title (english): Antioxidant activity of raw and roasted hazelnuts
• Author: Tamara Ciko
• Mentor: Ines Panjkota Krbavčić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Quality Control); (Laboratory for Food Chemistry and Biochemistry); Zagreb
• Defense date and country: 2012-06-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Cilj ovog rada bio je istražiti antioksidativnu aktivnost u svježim i prženim lješnjacima te kako vrijeme prženja utječe na količinu ukupnih fenola i antioksidativnu aktivnost. Svi su uzorci grubo usitnjeni i podvrgnuti vodenoj ekstrakciji kako bi se ekstrahirali fenolni spojevi. Za određivanje ukupnih fenola u uzorcima je korištena Folin-Ciocalteu metoda, a za određivanje antioksidativne aktivnosti se koristila DPPH metoda. Utvrđena je korelacija između količine fenolnih spojeva i antioksidativne aktivnosti u ovisnosti o vremenu prženja (r=0,99; p<0,001). U uzorku svježih lješnjaka je pronađena najveća količina ukupnih fenola (18,2 ± 0,85 mgGAE/g uzorka), slijedi uzorak pržen 10 minuta (16,8 ± 0,28 mgGAE/g uzorka), a u uzorku prženom 20 minuta je količina fenola najmanja (7,6 ± 0,28 mgGAE/g uzorka). Stoga je i antioksidativna aktivnost najveća u svježim lješnjacima u odnosu na pržene uzorke. Produljenjem vremena prženja dolazi do opadanja količine ukupnih fenola i posljedično smanjene antioksidativne aktivnosti.

Abstract (english)

The aim of this work was to evaluate antioxidant activity of raw and roasted hazelnuts according to their total phenol content. The influence of different roasting conditions ( 180°C/ 10 min and 180°C/ 20 min) was also examined and its effect on total phenol content and antioxidant activity. All samples were chopped in advance. Water extraction was used to extract phenolic compounds and then the obtained extracts were diluted. Folin-Ciocalteu method was used to examine total phenol content in hazelnut samples and DPPH radical-scavenging method to estimate antioxidant activity. Significant correlation was found between total phenol content and antioxidant activity due to longer roasting period (r=0,99; p<0,001). Raw samples had higher phenol content (18,2 ± 0,85 mgGAE/g sample) than samples roasted for 10 minutes (16,8 ± 0,28 mgGAE/g sample) and samples roasted for 20 minutes had the lowest phenol content (7,6 ± 0,28 mgGAE/g sample). Consequently, raw samples showed higher antioxidant activity in comparison with roasted ones. As a result of longer roasting period, both phenol content and antioxidant activity were decreased.

• Keywords: lješnjaci; ukupni fenoli; antioksidativna aktivnost
• Keywords (english): hazelnuts; total phenol content; antioxidant activity
• Language: croatian
• URN:NBN: urn:nbn:hr:159:061242
• Study programme: Title: Nutrition; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-16 08:55:43