The aim of this work was to investigate the ability of the NIR spectroscopy method to describe the physical and chemical changes occurring during wet agglomeration of wheat flour. The NIR spectra were analysed as raw spectra and after second derivative treatment by using principal components analysis (PCA). The results are discussed in terms of physical and chemical changes involved in wet agglomeration. The results confirm the ability of NIR spectroscopy to identify the wet agglomeration time of wheat flour (time necessary to obtain an homogenous distribution of particle size) and the possibility to propose physical and chemical analysis of NIR spectra. The spectra show that the most important physical and chemical modifications occurring during crumbly dough mixing are associated to the modifications of the glutenin depolymerisation, flour particle hydration and changes in particle size. (C) 2008 Published by Elsevier B.V.