Distribution of aroma in a starch–polysaccharide composite gel
Résumé
The location of different aroma compounds in a gel containing sucrose, cross-linked waxy corn starch and carrageenan was investigated. Different systems were designed by varying the carrageenan and the sucrose contents and were flavoured with a mixture of aroma compounds. These systems are described as composite gels formed by a dispersed phase composed of swollen starch granules and a continuous phase containing the other polysaccharide. The separation of the two phases was done by centrifugation. The concentration in aroma compounds was measured in both phases and a partition coefficient was calculated for every compound in the different formulations. When the gel contained only starch, the distribution between the two phases for all aroma compounds was uniform. When carrageenan was present, the aroma compounds were found to be more concentrated in the continuous phase than in the dispersed phase. The addition of sucrose induced the opposite effect with a greater concentration of aroma compounds in the dispersed phase. The combination of these results with those of the gas/matrix partition is finally discussed to understand how the distribution of aroma compounds in a biphasic system influences aroma release in the headspace under equilibrium.