Use of SNIF-NMR and IRMS in combination with chemometric methods for the determination of chaptalisation and geographical origin of wines (the example of Slovenian wines)

Isotopic ratios determined by SNIF-NMR and IRMS methods were used in combination with chemometric methods PCA, KANN and cluster analysis for the detection of wine chaptalisation and differentiation of wines according to the geographical origin. Selected wines from the three wine-growing regions of Slovenia were chosen for the analysis since Slovenia, small by surface, but pedologically and climatically diverse, offers interesting possibilities for studying the influence of this diversity upon the isotopic ratios in molecules of natural products. We found that the separation of wines of the Coastal region from the wines of the continental regions Sava and Drava is very good. On the other hand, the separation between wines from the Sava and the Drava region is not satisfactory. This is not surprising since the climatic differences between these two regions are small when compared with the differences between the continental and Coastal regions. Regarding the chaptalisation, the considerable improvement by combining both SNIF-NMR and IRMS is obtained. PCA and KANN give comparable separation of wines according to the geographical origin, but PCA is less time consuming. In the case of enrichment of wines from the Drava region by beet sugar better separation between natural and enriched wines is obtained using KANN method. In all cases cluster analysis shows poorer efficiency than PCA and KANN. (C) 2001 Elsevier Science B.V. All rights reserved.