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

Figure 4

Results of discrimination by origin. In the coloured plots, blue is ¹H-NMR, black is ATR-mIR, and red is NIR. values as a function of the number of components in the model (left), ROC curves (center), and area under the ROC curve for all models represented as box plots (right). The upper panel shows results using a standard 7-fold cross-validation, while the lower panel shows results obtained with a 100-model Monte Carlo cross-validation.