Fat and flavour are important factors in food acceptance and can affect the partitioning of hydrophobic flavour molecules (1).The equilibrium retention release has been studied most frequently for inhomogeneous products (2, 3), than for thickeners separately (4). Pectin and carrageenans are common used thickeners, and the aim of this work was to study and to compare their respective effects on the aroma release. In this way, the release of 13 aroma compounds was analyzed by headspace analysis at equilibrium for pure water, i-carrageenan and pectin gels. To evaluate the influence of the chemical structure of aroma compounds on retention/release equilibrium between vapour phase and gels, we used QSAR approach in order to investigate the nature of involved interactions in complex food matrices. QSPR methods attempt to find relationships between the properties of molecules and an experimental response; the assumption is that changes in molecular properties elicit different responses. The QSPR study is intended to represent a physico-chemical property into a simple mathematical relationship, the QSAR equation: ER=f(p1, p2, p3, …pn) where ER is the experimental partition coefficient. Our present aim consist first to all to find relationships between experimental response and the aroma structure, reflected by molecular descriptor values, to identify some relevant structural properties related to the retention and to propose a qualitative interpretation. Our result highlight the role of polar effects on the retention of odorant molecules and put forward that retention/release properties are not determined by the chemical classes, but by an ensemble of chemical properties. In this way, QSPR approach constitutes a promising tool for characterising of interactions involved in complex food matrices. References: (1) Guichard, E. (2002) Interactions between flavor compounds and food ingredients and their influence on flavor perception. Food Rev. Int. 18, 49-70. (2) De Roos, K. (2003) Effect of texture and microstructure on flavor retention and release. Int. Dairy J. 13, 593-605. (3) Lubbers, S., Decourcelle, N., Martinez, D., Guichard, E. & Tromelin, A. (2007) Effect of thickeners on aroma compound behavior in a model dairy gel. J. Agric. Food Chem. 55, 4835-4841. (4) Hansson, A., Leufven, A., Pehrson, K. & B., S. (2002) Multivariate analysis of the influence of pectin, white syrup, and citric acid on aoma concentration in the headspace above pectin gels. J. Agric. Food Chem. 50, 3803-3809.