Rapid Measurement of Phenolics Compounds in Red Wine Using Raman Spectroscopy

This paper presents the development of a new method to measure the main phenolic compounds found in Cabernet Sauvignon red wines. A portable Raman spectrometer was used for this purpose, providing scattering spectra to analyze quantitatively the samples and determining the concentration of the compounds of interest. The Raman spectra were obtained from the wine samples corresponding to different seasons, vineyards, and harvests. The subsequent model calibration was based on reference analytical values obtained using standard laboratory techniques. Several preprocessing and correlation methods were applied to the data in order to adjust models for polyphenols, anthocyanins, and tannins and also to reduce the effect of fluorescence. The optimization of the models was carried out using R2and root-mean-square error of validation (RMSEV) indices. The correlations of R2= 0.895 and RMSEV = 5.55 mg/L were obtained, showing the potential of this technique for field measurements.