Near Infrared Spectroscopy: Easy and Rapid Tool to Determine Different Volatile Compounds in Wines

The aim of this paper was to review the ability of NIR spectroscopy to determine fermentative volatile compounds, oak volatile compounds, ethylphenols, haloanisoles, and halophenols in aged red wines, which are the highest quality and reputation in the market. Six hundred wines from four different Spanish geographic zones aged during different storage time (at least 6, called as “crianza”, 12, called as “reserva”, and 18 months, called as “gran reserva”) in different oak barrel types were evaluated. These four zones commercialized around 72% of all red wines in Spain and were representative of the entire Spanish territory. Spectra of samples obtained by NIR were co-related with SBSE-GC-MS volatile compounds data using partial least squares regression. For fermentative compounds, results showed that the calibration statistics were excellent (R2>0.98). Validation statistics showed the quality of the model, especially when was done separately for each of the four zones and for wines elaborated with two different grape varieties; in general, the residual predictive deviation (RPD) was higher than 1.5. For oak compounds and ethylphenols, the calibration statistics were also very good (R2>0.86). In wines aged in French and in American and French oak barrels, and in “reserva” and “gran reserva” wines, the RPD was higher than 1.5 in all the compounds. For haloanisoles and halophenols, favourable calibration results were obtained (R2>0.77). The RPD values over 1.5 were obtained for “reserva” and “gran reserva” wines as well as for three of the four zones. Consequently, NIR spectroscopy can be used as a rapid tool to determine fermentative volatile compounds, oak volatile compounds, ethylphenols, haloanisoles, and halophenols in wines.