Study of interaction phenomena between aroma compounds and carbohydrate matrixes by inverse gas chromatography

Besides the conventional techniques used for the investigation of food-flav or interactions, inverse gas chromatography (IGC) may provide a useful tool for the direct assessment of the retention of aroma compounds in a matrix. IGC consists of single reference compound injections at a fixed temperatur e onto a column which stationary phase is the material of interest. We have applied this technique to high amylose corn starch, wheat starch, and beta -cyclodextrin matrixes, using aroma compounds presenting various functional groups. Low energy interactions were measured which may result from polar or hydrophobic binding. Starch behaved under these conditions as a polar ch romatographic phase. We also focused on the influence of a physical modific ation of the starch on its retention properties toward 3,7-dimethyl-2,6-oct adien-1-al, Retention was found to be greater after a specific thermal trea tment. As checked by DSC (differential scanning calorimetry) and DMTA (dyna mic mechanical and thermal analysis), the observed changes are believed to be related to the glass transition of the starch. For the time being, the d ehydration of the matrix associated with the lack of control of the relativ e humidity within the column is the main restriction to this technique.