The characterization of aroma mobility within foods is an important challenge for a better understanding of aroma release in relation to product structure and perception but is difficult to achieve. An experimental device, based on the diffusion cell concept, was used to determine the apparent diffusivity of aroma compounds within complex food products using gaseous measurements. The originality of our approach was based on a mechanistic description of the system and on the early integration of modeling, leading to an apparatus especially adapted for complex matrices and easy to use (direct analysis and no sample storage). The impacts of the operating conditions and of the data treatment analysis on the accuracy of the determination of apparent diffusion properties were evaluated for three aroma compounds in model agar gels. The comparison of these diffusion results with data found in the literature demonstrated the reliability and the robustness of the system. Its suitability for the characterization of mobility properties of aroma compounds in real food matrices was achieved using dairy gels. (c) 2007 Elsevier Ltd. All rights reserved.