Table 2.

Performance of the PLS regression model for moisture content in single green coffee beans.

Parameter	Pre-processing	LV	R2 Cal	RMSEC	Slope	R2 Val	RMSECV	Slope	RPD
Natural moisture content	Log (1/R)	8	0.842	0.291	0.815	0.819	0.312	0.828	2.53
	Mean centered	8	0.844	0.289	0.844	0.825	0.307	0.834	2.57
	First derivative	11	0.899	0.233	0.899	0.858	0.276	0.879	2.86
	Second derivative	12	0.898	0.237	0.898	0.813	0.322	0.852	2.45
	SNV	12	0.897	0.235	0.897	0.850	0.285	0.872	2.77
Laboratory-treated beans	Log (1/R)	5	0.951	2.234	0.951	0.950	2.279	0.949	4.73
	Mean centered	5	0.947	2.314	0.947	0.947	2.372	0.946	4.54
	First derivative	5	0.966	1.916	0.966	0.963	1.999	0.965	5.39
	Second derivative	4	0.957	2.209	0.957	0.955	2.266	0.955	4.75
	SNV	3	0.962	2.041	0.963	0.912	2.074	0.962	5.19

Spectral range used: 980-2480 nm. LV: latent variable. SNV: standard normal variate spectral treatment. Error is indicated as %. RPD: ratio of performance deviation. Sample size (n): 320.