Corncobs were reacted with water and treated at temperatures in the range 145-190 degreesC during 0-12.3 h at a liquor to solid ratio of 8 or 10 kg/kg (autohydrolysis treatments), to hydrolyse the hemicellulose fraction to xylooligomers (useful as food ingredients) and xylose (a carbon source for further fermentation stages). The time-courses of xylan and xylan-degradation products (including xylooligomers, xylose, furfural and other degradation products) were established. The kinetics of xylan degradation was modelled by means of a mechanism involving sequential, first order, pseudohomogeneous kinetics. The Values of the kinetic coefficients were calculated, and their dependence on temperature was established using Arrhenius-type equations. The proposed model provides a satisfactory interpretation of the experimental data, allowing the selection of optimized operational conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.