NEAR INFRARED SPECTROSCOPY FOR THE ESTIMATION OF TEMPRANILLO BLANCO VOLATILE COMPOSITION ALONG GRAPE MATURATION
Grape volatile compounds are mainly responsible for wine aroma, so it is important to know the varietal aromatic composition throughout ripening process. Currently, there are no tools that allow measuring the aromatic composition of grapes, in intact berries and periodically, throughout ripening, in the vineyard or in the winery. For this reason, this work evaluated the use of near infrared spectroscopy (NIR) to estimate the aromatic composition and total soluble solids (TSS) of Tempranillo Blanco berries during ripening. For this purpose, NIR spectra (1100-2100 nm) were acquired from 240 samples of in-tact berries, collected at different dates, from veraison to overripening. From these same samples, the concentration of volatile compounds was analyzed using Thin Film-Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (TF-SPME-GC-MS), and the TSS were quantified by refractometry. Calibration, cross-validation and prediction models were built from spectral data using modified partial least squares regression (MPLS). Determination coefficients of cross-validation (R²CV) above 0.5 were obtained for all volatile compounds, their families, and TSS. These findings support that NIRS can be successfully use to estimate the aromatic composition as well as the TSS of intact Tempranillo Blanco berries in a non-destructive, fast, and contactless form, allowing simultaneous determination of technological and aromatic grape maturities.
Issue: OENO Macrowine 2023
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grape aromatic composition, NIR spectroscopy, non-destructive, TF-SPME