Monitoring of Alcoholic Fermentation Using NIR and MIR Spectroscopy combined with Electronic Nose and Electronic Tongue

The rapid pace of change in the wine industry calls for fast methods providing real time information in order to assure the quality of the final product. NIR and MIR spectroscopy combined with sensory-instrumental methods (electronic nose and electronic tongue) can provide an ideal solution to monitor molecular and sensory changes in wine during alcoholic fermentation. The objective of this work was to investigate the potential of NIR and MIR spectroscopy, electronic nose and electronic tongue associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Twenty-three micro-fermentation trials were conducted during the 2008-2009 vintages in Valtellina viticultural area (Northern Italy). During fermentation, at each sampling time, spectra were collected by FT-NIR and FT-IR spectrometers and samples were analysed by electronic nose and electronic tongue. Chemical analyses were performed to evaluate sugar, phenolic compounds, ethanol and glycerol concentrations. Various multivariate statistical methods were applied in order to obtain regression and classification models. Results showed that FT-NIR and FT-IR spectroscopy can provide good regression PLS models to predict the main chemical parameters involved in alcoholic fermentation. Classification techniques (LDA, QDA, genetic algorithms) were applied to electronic nose, electronic tongue and spectral data, obtaining sample classification based on fermentation stages