Predicted versus measured values of carbohydrate release following pretreatment and enzymatic hydrolysis. The x-axis represents release values obtained from primary methods measured in grams per gram. The y-axis represents values for carbohydrates released in grams per gram as predicted on the PLS-2 calibration equation for glucose and xylose separately (G.Release and X.Release), or as predicted on the PLS-1 calibration equation for the sum of glucose and xylose released (GX.Release). Predictions are from the calibration models. (A) Predicted versus measured values of carbohydrate release for the calibration samples. (B) Predicted versus measured values of carbohydrate release for the 18 external validation samples.