Sorghum straw is a raw material useful for the xylose production by hydrolysis. The main application of xylose is its bioconversion to xylitol, a functional sweetener with important technological properties. The objective of this work was to study the hydrolysis of sorghum straw with hydrochloric acid at 100 degreesC. Several concentrations of HCl (2-6%) and reaction time (0-300 min) were evaluated. Kinetic parameters of mathematical models for predicting the concentration of xylose, glucose, acetic acid and furfural in the hydrolysates were found and used to optimise the process and compared with results reported in the literature using other conditions and acids. Optimal conditions found for hydrolysis were 6% HCl at 100 degreesC for 83 min, which yielded a solution with 21.3 g xylose/l, 4.7 g glucose/l, 0.8 g furfural/l and 2.8 g acetic acid/l. (C) 2003 Elsevier Ltd. All rights reserved.