CHARACTERIZATION OF RED GRAPES SKIN EXTRACTS USING VIBRATIONAL SPECTROSCOPY AND CHEMOMETRICS

The study aims a chemometric-based vibrational spectroscopy investigation, Fourier transform infrared (FTIR) and Raman spectroscopy, on the hydroalcoholic extracts obtained from four variety of red grapes (skin). The multivariate analysis, by combining both principal component analysis (PCA) and linear discriminant analysis (LDA) approaches (called PC-LDA model), applied on the FTIR and Raman spectral data was performed to determine the differences in the chemical composition according to the red grapes variety and the type of vineyards (i.e. conventional or traditional and ecological), correlated also with antioxidant activity and total phenolic content values of the extracts. By applying PC-LDA model a separation between extracts from different vineyads can be observed. A well-defined differentiation based on antioxidant activity and total phenolic content could not be highlighted. Among the extracts, those obtained from ecological varieties showed the greatest similarity, indicating that these extracts have equivalent chemical composition.