Enzymatic hydrolysis of cheese whey proteins with immobilized enzymes, providing a tailor-made pool of peptides, within narrow ranges of molecular weight, might be an advantageous alternative for this by-product of the dairy industry. In this work, Alcalase(R) was immobilized in agarose-glyoxyl gel beads and the proteolysis reaction was run in a continuous Taylor-Couette-Poiseuille reactor [or vortex flow reactor (VFR)], which presented efficient stirring without damaging the fragile beads. VFR mass transfer parameters were estimated after residence time distribution assays. Artificial neural networks were used to predict reaction rates of five ranges of peptide molecular weights. Using this hybrid model, a detailed description of the system was achieved. A bench-scale VFR (radius ratio eta = 0.48 and aspect ratio Gamma = 11.9) was used to validate the model. (C) 2004 American Institute of Chemical Engineers.