RT Journal Article
SR Electronic
T1 Application of NIR-AOTF Spectroscopy to Monitor Aleatico Grape Dehydration for Passito Wine Production
JF American Journal of Enology and Viticulture
JO Am. J. Enol. Vitic.
FD American Society for Enology and Viticulture
SP ajev.2010.10041
DO 10.5344/ajev.2010.10041
A1 Andrea Bellincontro
A1 Daniel Cozzolino
A1 Fabio Mencarelli
YR 2011
UL http://www.ajevonline.org/content/early/2011/02/23/ajev.2010.10041.abstract
AB Aleatico (Vitis vinifera L.) grapes were harvested at 21.3 Brix and dehydrated at 20°C, 45% relative humidity, and 1.5 m/s air flow in a small scale thermo-conditioned tunnel. Postharvest grape drying was performed until the fruit lost an average of 40% of its initial weight. During dehydration, single destemmed grape berries were analyzed non-destructively using an Acousto Optically Tunable Filter (AOTF) Near-Infrared (NIR) spectrophotometer (1100–2300 nm) in reflectance. Total soluble solids (TSS, Brix) and moisture content (%) were measured on the same berries with the objective of using spectral and non-spectral information to develop regression models for predicting these parameters. Partial Least Square (PLS) applied after different statistical pre-treatments (Multiplicative Scatter Correction, Savitzky-Golay 1st or 2nd derivative filter) was tested on absorbance spectra in order to define the most effective approach. Two prediction models were obtained (n = 450 for TSS, and n = 600 for water loss) in which the coefficient of determination in cross-validation (r2) and the root mean standard error of cross-validation (RMSECV) were 0.93 and 0.89 Brix for TSS and 0.92 and 2.16% for water loss, respectively. A model validation procedure was performed using separate sample sets (n = 170 for TSS, and n = 200 for water loss) with the following results: coefficient of determination (R2) and standard error of prediction (SEP) of 0.92 and 0.72 Brix for TSS and 0.9 and 1.89% for water loss, respectively.