Soluble sugar FTIR PLS prediction models. PLS prediction of (A) sucrose (mM), (B) glucose (mM), and (C) fructose (mM) in an independent test set of S. bicolor juice mixtures. Predictions are plotted against the known reference values for each sample. Calibration samples (○) and independent validation samples (•) were overlaid on a target line (y = x). The coefficient of determination (R2) and root mean square error (RMSE) for each sample set are displayed for each sugar. FTIR, Fourier transform infrared; PLS, partial least squares; RMSE, root mean squared error.