The fluorescence of the sugar can hence be regarded as a global quality indicator for the sugar. Figure 3 . In bi-PLS2 these are unfolded to matrices. However, the loadings of the two models have quite different degrees of interpretability. Figure 4 .
Interpretation is difficult due to confounded orders.
Figure 5 . Loadings from quadri-PLS3 in the three orders. The N-PLS proposed, is a natural extension of the bilinear PLS model. In this case no real improvement in the predictions was achieved. However, a huge simplification of the model was obtained, yielding a much more interpretable model.