Table 1.

Calibration, cross-validation, and external validation (prediction) of the best models obtained to predict the total soluble solids, anthocyanins and total polyphenols concentrations in grape clusters under field conditions from on-the-go Vis + SW − NIR spectroscopy (570–990 nm).

						Calibration		Cross-Validation		External Validation
Parameters	Spectral Treatment	N	SD	Range	PLS Factor	RMSEC	R2c	RMSECV	R2cv	RMSEP	R2p
Total soluble solids (°Brix)	D1W15	116	4.403	10.70–25.20	7	1.119	0.93	1.248	0.92	1.011	0.95
Anthocyanins (mg/berry)	D1W15	116	1.329	0.09–4.64	6	0.607	0.79	0.664	0.75	0.618	0.79
Total polyphenols (Au/berry)	SNV + DT D1W15	116	0.947	0.14–4.70	7	0.642	0.54	0.728	0.42	0.749	0.43

SNV: standard normal variate. DnWm, Savitzky–Golay filter with n-degree derivative, window size of m. N: number of samples used for calibration and cross-validation models after outlier detection. SD: standard deviation. RMSEC: root mean square error of calibration. R²_c: determination coefficient of calibration. RMSECV: root mean square error of cross-validation. R²_cv: determination coefficient of cross-validation. RMSEP: root mean square error of prediction. R²_p: determination coefficient of prediction.