Possibilities of organic and conventional wines differentiation on the basis of multivariate analysis of their characteristics (EPR, UV–Vis, HPLC and AAS study)

Abstract

Proving of affiliation of wine sample to either organic or conventional production system and of its geographical origin although important both for consumer safety and food control authorities is still problematic. Characteristics of Slovak and some European wines obtained by spectroscopic methods including atomic absorption spectroscopy, electron paramagnetic resonance spectroscopy (EPR) and ultraviolet–visible spectroscopy in combination with high-performance liquid chromatography and isotachophoresis processed subsequently by multivariate statistics were successfully used to differentiate Slovak organic and conventional wines according to their affiliation to production system and, at the same time, to differentiate the Slovak organic and conventional wine samples from those, produced in other European countries. From totally 74 determined experimental characteristics, concentration of Fe and Cu, ferric-reducing power values, Trolox-equivalent antioxidant capacity values evaluated from ·DPPH assay by EPR (\(\tiny \small \text{TEAC}_{{^{\cdot} \text{DPPH(EPR)}}}\)), ascorbic acid equivalents (AAE), % of radicals scavenged, concentration of citric acid, catechin and epicatechin, but also color values a* and chromaticity were identified by ANOVA, Tukey’s HSD multiple comparison and stepwise discrimination tests as the most promising characteristics for white wines differentiation, whereas Fe content and AAE for the differentiation of red wines. Recognition and prediction ability tests of the Slovak white organic and conventional wines reached 100 %, whereas in case of red wines, correctness of recognition reached 90.5 % and of the prediction ability, 90 %. High correctness of differentiation of organic and conventional samples according to the origin of wine was obtained, reaching 95.8 % for white wines and 80.7 % for red wines, with two Slovak wines misclassified as wines of Czech origin.