Original scientific paper

https://doi.org/10.5562/cca3120

Electrochemical and Spectrophotometric Determination of Total Polyphenol Content in Croatian Apple Varieties

Martina Medvidović-Kosanović orcid.org/0000-0002-9887-9169 ; Department of Chemistry, University of Osijek, Cara Hadrijana 8A, 31000 Osijek, Croatia
Anamarija Šter ; Department of Chemistry, University of Osijek, Cara Hadrijana 8A, 31000 Osijek, Croatia
Lidija Jakobek orcid.org/0000-0002-4846-327X ; Faculty of Food Technology Osijek, University of Osijek, Kuhačeva 20, 31000 Osijek
Petra Krivak ; Faculty of Food Technology Osijek, University of Osijek, Kuhačeva 20, 31000 Osijek
Rebecca Mađarić orcid.org/0000-0002-1499-3520 ; Department of Chemistry, University of Osijek, Cara Hadrijana 8A, 31000 Osijek, Croatia

Abstract

Oxidation mechanism of quercetin in three different electrolytes (KCl, NaCl and LiCl) was studied by cyclic and differential pulse voltammetry. The results have shown that quercetin oxidation is reversible and diffusion controlled process in all three investigated electrolytes. Calibration diagram of quercetin was obtained in KCl, so this electrolyte was selected for total polyphenol content determination in apple peel extracts. Total polyphenol content was analysed by differential pulse voltammetry (dpv) and spectrophotometric Folin-Ciocalteu method (FC) in several ancient Croatian apple varieties and a wild apple variety grown in Croatia by using quercetin as a standard. Very high correlation for TP content obtained by two methods was observed since the TPdpv/TPFC ratio was around 1 and a correlation coefficient (R2) for TPdpv vs. TPFC was 0.98. The highest total polyphenol content was found in Slavonska srčika variety.

This work is licensed under a Creative Commons Attribution 4.0 International License.

Keywords

apple extracts; differential pulse voltammetry; spectrophotometry; quercetin; polyphenol determination

Hrčak ID:

183705

URI

https://hrcak.srce.hr/183705

Publication date:

3.7.2017.

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