doctoral thesis
Characterization of chlorogenic acids and analysis of antioxidation activity in different coffee varieties using electrochemical methods

Ivana Tomac (2016)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Sub-department of Applied Chemistry and instrumental Methods
Engineering Chemistry
Metadata
TitleKarakterizacija klorogenskih kiselina i analiza antioksidacijske aktivnosti u različitim vrstama kave primjenom elektrokemijskih metoda
AuthorIvana Tomac
Mentor(s)Marijan Šeruga
Abstract
U ovoj disertaciji provedena je karakterizacija klorogenskih kiselina (CGAs) i analiza antioksidacijske aktivnosti u različitim vrstama kave (zelenim i prženim zrnima kave C. arabica i C. robusta, mljevenim kavama Franck Guatemala i Flatcher Olympia te instant kavama Nescafé Classic, Nescafé Espresso, Jacobs Monarch i Jacobs Intense). Prije karakterizacije CGAs, istražena su elektrokemijska svojstva kafeoilkina kiselina (CQAs), dikafeoilkina kiselina (diCQAs) i feruloilkina kiselina (FQAs) primjenom pravokutnovalne voltametrije (SWV), diferencijalne pulsne voltametrije (DPV) i protočne stripping kronopotenciometrije (FTSCP). Elektrokemijska mjerenja CGAs utvrdila su da se na površini radne elektrode odvijaju različite elektrokemijske reakcije različitim oksidacijskim mehanizmima, ovisno o kemijskoj strukturi CGAs. Karakterizacija CGAs provedena je primjenom metoda SWV, DPV, FTSCP i HPLC. Identifikacija i kvantifikacija CGAs u kavama pokazala je da najveći sadržaj ukupnih CGAs imaju zelena zrna kava. Antioksidacijska aktivnost CQAs i diCQAs istraživana je primjenom elektrokemijskog DNA biosenzora, dok je antioksidacijska aktivnost kave istraživana i primjenom DPPH i ABTS metode. Analiza antioksidacijske aktivnosti CQAs i diCQAs primjenom DNA biosenzora pokazala je ovisnost o kemijskoj strukturi ispitivanih klorogenskih kiselina. DNA biosenzor, ABTS i DPPH metode pokazale su da najveću antioksidacijsku aktivnost imaju uzorci zelenog zrna kave, zbog najvećeg sadržaja ukupnih CGAs. Istraživanjima je utvrđeno da postoji vrlo dobra do izvrsna korelacija između antioksidacijske aktivnosti kava i sadržaja ukupnih CGAs.
Keywordspolyphenols coffee electrochemical methods antioxidant activity
Parallel title (English)Characterization of chlorogenic acids and analysis of antioxidation activity in different coffee varieties using electrochemical methods
Committee MembersDrago Šubarić (committee chairperson)
Marijan Šeruga (committee member)
Igor Jerković (committee member)
Lidija Jakobek (committee member)
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsSub-department of Applied Chemistry and instrumental Methods
Engineering Chemistry
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
UDK54
NATURAL SCIENCES
Chemistry. Crystallography. Mineralogy
663
APPLIED SCIENCES. MEDICINE. TECHNOLOGY
Industrial microbiology. Industrial mycology. Zymurgy, fermentation industry. Beverage industry. Stimulant industry
Study programme typeuniversity
Study levelpostgraduate
Study programmeFood Engineering
Academic title abbreviationdr. sc.
Genredoctoral thesis
Language Croatian
Defense date2016-06-17
Parallel abstract (English)
In this study, the characterization of chlorogenic acid (CGAs) and the analysis of antioxidant activity in different brands of coffee (green and roasted beans C. arabica and C. robusta, ground coffee Franck Guatemala and Flatcher Olympia, and instant coffee Nescafé Classic, Nescafé Espresso, Jacobs Monarch and Jacobs Intense) were investigated. Before the characterization, the electrochemical properties of the caffeoylquinic acids (CQAs), dicaffeoylquinic acids (diCQAs) and feruloylquinic acids (FQAs) were analysed by the square-wave voltammetry (SWV), differential pulse voltammetry (DPV) and flow through stripping chronopotentiometry (FTSCP). The electrochemical measurements of the CGAs have shown that on the surface of the working electrode, the different electrochemical reactions via different mechanisms of oxidation proceeded, in connection with the chemical structure of CGAs. Characterization of CGAs was performed by SWV, DPV, FTSCP and HPLC methods. The identification and quantification of the CGAs in different brands of coffee were performed by the SWV, DPV, FTSCP and HPLC methods. The results have shown that the highest CGAs total content exists in the green coffee beans. The antioxidant activity CQAs and diCQAs were analysed by DNA-biosensor while the antioxidant activity of coffee was analysed also by DPPH and ABTS methods. Antioxidant analysis of CQAs and diCQAs using DNA-biosensors has shown the dependence on the chemical structure of investigated CGAs. The methods of DNA-biosensor, ABTS and DPPH have shown the highest antioxidant activity in the green coffee beans due to the highest content of the total CGAs. Very good to the excellent correlation between the antioxidant activity of coffee and the CGAs total content was observed in this study.
Parallel keywords (Croatian)polifenoli kava elektrokemijske metode antioksidacijska aktivnost
Extent30 x 21; [9], 230 str.: ilustr. u boji, graf. prikazi:+ 1 CD
Versionaccepted version
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
Noteaccepted version
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:938176
CommitterIvana Šuvak