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

Besides the conventional techniques used for the investigation of food-flavor 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 temperature 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 chromatographic phase. We also focused on the influence of a physical modification of the starch on its retention properties toward 3,7-dimethyl-2,6-octadien-1-al. Retention was found to be greater after a specific thermal treatment. As checked by DSC (differential scanning calorimetry) and DMTA (dynamic mechanical and thermal analysis), the observed changes are believed to be related to the glass transition of the starch. For the time being, the dehydration of the matrix associated with the lack of control of the relative humidity within the column is the main restriction to this technique.