Thermodynamic and kinetic study of volatile compounds in biopolymer based dispersions

Partitioning and release of ethyl acetate and diacetyl from two matrices with a different composition was studied by applying static head space gas chromatography. Two matrices with a different composition have been developed: one containing carbohydrates (Tragacanth gum) and in the second one, called complex matrix, a lipid (oleic acid) was added. The roles of carbohydrate (Tragacanth gum) and lipid (oleic acid) on the retention of all the aroma compounds were pointed out. Changes in the composition of matrices exhibited a considerable effect on the thermodynamic component as expressed by the air/liquid partition coefficient (Ka/l) values at equilibrium (20 °C). The kinetic study of the release from these matrices had shown a decrease of the initial rate of release (Ri) by reference with water. The rheological properties of all matrices were investigated and the flow behaviour of all matrices was successfully modelled with power law and Ellis models and power law model was found as the better model to describe the flow behaviour of dispersions.