Ultraviolet – visible - near infrared spectroscopy for rapid determination of volatile compounds in white grapes during ripening

Resumo

Near Infrared (NIR) spectroscopy is increasingly used in food analysis due to its speed and ease of use. Ultraviolet-visible (UV-VIS) spectroscopy is commonly used in any laboratory worldwide. The objective of this work was to develop a rapid method based on UV-VIS-NIR spectroscopy for the determination of volatile compounds in white ‘Albariño’ grapes from DO Rias Baixas (Spain). A total of 52 samples of white ‘Albariño’ must were analysed. Gas chromatography-mass spectrometry (GC-MS) was used as reference method. Partial Least Squares regression was used to fit mathematical models to relate the UV-VIS-NIR spectra with the volatile compounds determined by GC-MS. Reliable models for predicting the following compounds were obtained: (E)-2-hexenal, 1-hexanol, (Z)-2-hexanol, benzaldehyde, phenylethanal, cis pyran linalool oxide and 2- phenylethanol. The best performance was obtained using pre-treated spectral data (1st and 2nd derived). The r2 coefficients obtained were greater than 0.85 for these compounds. In conclusion, UV-VIS-NIR spectroscopy is a fast and feasible method for the determination of some volatile compounds in white ‘Albariño’ musts from DO Rías Baixas.