Comparison of Attenuated Total Reflectance Mid-Infrared, Near Infrared, and ¹H-Nuclear Magnetic Resonance Spectroscopies for the Determination of Coffee’s Geographical Origin

Figure 3

Loadings stability analysis. The first loadings vector was sorted before plotting. The smooth and coloured curve that drops from left to right corresponds to the values of the loadings in decreasing order. The oscillating curve falling from right to left corresponds to the relative error (std. dev./mean) of these loadings. Above each plot, the corresponding preprocessed spectrum prior to scaling, sorted to match the loadings’ order. Results shown were obtained for the 7-fold validation, and results for the Monte Carlo validation are virtually identical.