Usporedba ispitivanja antioksidansa u vinu elektrokemijskom metodom cikličke voltametrije i kemijskim metodama

master's thesis

• Title (english): Comparison of wine antioxidant testing by the electrochemical method of cyclic voltammetry and by chemical methods
• Author: Ivan Aleksandar Kelava
• Mentor: Sanja Martinez (mentor)
• Committee member: Sanja Martinez (predsjednik povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Committee member: Lidija Furač (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-07-12, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

U ovom radu ispitano je deset uzoraka vina hrvatskih proizvođača metodom cikličke voltametrije u fosfatnom puferu. Staklena ugljična elektroda korištena je kao radna elektroda, a antioksidacijski kapacitet određen ovom metodom uspoređen je s antioksidacijskim kapacitetom određenim kemijskim metodama: FRAP, ABTS i DPPH. Askorbinska kiseline, koja ima sličan mehanizam oksidacije kao i polifenolni spojevi niže molekulske mase koji u svojoj strukturi sadrže orto-dihidroksi fenolnu skupinu, korištena je kao standard za određivanje antioksidacijskog kapaciteta uzoraka vina kemijskim i elektrokemijskim metodama. Antioksidacijski kapacitet iskazan je kao ekvivalent askorbinske kiseline, izražen u jedinicama mmol AAE / 100 g uzorka. Postignuta je pozitivna, srednje jaka korelacija antioksidacijskog kapaciteta između ispitanih metoda. Kod svih metoda određivanja crna vina pokazala su značajno više vrijednosti antioksidacijskog kapaciteta u odnosu na bijela i ružičasta vina.

Abstract (english)

This work examined ten samples of wines of Croatian producers' with the cyclic voltammetry method in phosphate buffer. The glassy carbon electrode was used as a working electrode, and the antioxidant capacity determined by this method was compared with the antioxidant capacity determined by the following chemical methods: FRAP, ABTS and DPPH. Ascorbic acid, having a mechanism of oxidation similar to the lower molecular weight polyphenolic compounds which contain ortho-dihydroxy phenol group in their structure, was used as a standard for determining the antioxidant capacity of wine samples by chemical and electrochemical methods. Antioxidant capacity is given in the equivalents of ascorbic acid and expressed in units of mmol AAE / 100 g sample. A positive correlation of medium strength was found between antioxidant capacities obtained by the tested methods. In all tested methods, black wines have shown significantly higher values of antioxidant capacity compared to white and pink wines.

• Keywords: ciklička voltametrija; antioksidansi; antioksidacijski kapacitet; askorbinska kiselina
• Keywords (english): cyclic voltammetry; antioxidants; antioxidant capacity; ascorbic acid
• Language: croatian
• URN:NBN: urn:nbn:hr:149:996550
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2022-02-21 15:00:40